Wmi Alhap Final Report 2005

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Alberta Hail Suppression Project 2005 Field Program Final Report Page: 2

Weather Modification Inc. October 2005

ALBERTA HAIL SUPPRESSION PROJECT

FINAL REPORT2005

Terry W. [email protected]

Editor

A Program forSeeding Convective Cloudswith Glaciogenic Nuclei to

Mitigate Urban Hail Damage in theProvince of Alberta, Canada

By

Weather Modification Inc.3802 - 20thStreet North

Fargo, North DakotaU.S.A. 58102

www.weathermod.com

For

Alberta Severe Weather Management Society

Calgary, AlbertaCanada

October 2005


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EXECUTIVE SUMMARY

This report summarizes the activities and data collected during the 2005 field operations of the AlbertaHail Suppression Project. This was the tenth year of operations by Weather Modification Inc. (WMI) ofFargo, North Dakota under contract with the Alberta Severe Weather Management Society of Calgary,

Alberta. The program continues to be funded entirely by private insurance companies in Alberta withthe sole intent to mitigate the damage to urban property caused by hail. This cloud-seeding projectstarted a second five-year term in 2001 because the insurance losses due to hail were approximately

50% less than expected for the first five-year project 1996-2000. The project design has remained thesame throughout the period. The project area covers the region from High River in the south toLacombe in the north, with priority given to the two largest cities of Calgary and Red Deer. Theprogram was operational from June 1

stto September 15

th, 2005.

Hail fell within the project area on 31 days. Larger than golf ball size hail fell early on the morning ofJuly 16thnear Vulcan, and on the afternoon of July 20 thnear Beiseker. Golf ball size hail was reportedon two days (July 28thnear Bergen, and July 29thnear Spruce View). Walnut size hail was reported onone day (July 19th) in south Calgary producing some damage over a small area. The cities and townswithin the project area were almost completely free of damaging hail, and the preliminary estimates ofproperty insurance claims for the project area this summer are once again much lower than theprevious 10-year non-seeded average. The most damaging storm of the year in terms of propertydamage occurred in Medicine Hat on June 17

th when golf ball size hail caused extensive damage.

Province wide, 2005 was an above-average year for the number of hail days but below average for thenumber of severe hail days.

For the entire Province of Alberta, the Alberta Agriculture Financial Services Corporation reported haildamage to crops on 71 days (3 days in May, 21 days in June, 23 days in July, 16 days in August, and 8days in September). Golf ball size hail was reported on 5 days (June 17thand 21st, July 16thand 20th,and September 3rd) this summer in Alberta. Preliminary data from crop insurance claims indicates thatcrop damage was approximately 48% below average this year.

During this season, there were 80 aircraft flights totaling 157.9 hrs on 36 operational days. There weretwo days with only test flights. A total of 70 storms were seeded during 60 seeding flights (131 hrs) on27 days on which seeding took place. There were 14 patrol flights (21.9 hrs) and 6 test flights (5 hrs).The amount of silver-iodide nucleating agent dispensed during the 2005 field season totaled 159.1 kg:

consisting of 3770 ejectable (cloud-top) flares (75.4 kg seeding agent), 515 end-burning (cloud-base)flares (77.25 kg seeding agent), and 94.2 gallons of AgI-acetone solution (6.46 kg seeding agent).

The notable weather story this summer for our area was the heavy rainfall, flood conditions, and coolerconditions across southern Alberta. The Pacific Ocean sea surface temperature anomalies wereslightly positive and can be classified as weak El Nino or neutral. For some unexplained reason,numerous cut-off, cold upper Low pressure systems formed regularly in the Gulf of Alaska and thenslowly tracked across BC and Alberta, bringing heavy rainfall events to southern Alberta. Four suchsystems occurred during June alone, saturating the soil and causing flooding in High River, Okotoks,Calgary, Sundre, and Red Deer. There were frequent rainfall events at Calgary and Red Deerthroughout the summer and the accumulated rainfall was greater than the normal value throughout thesummer in Calgary (131.7 mm above average), and most of the summer in Red Deer (52.4 mm aboveaverage). Calgary set a new record for the most rain in a single month. The average June rainfall is 79mm and the previous record rainfall in June was 224 mm. During June 2005, Calgary received 246mm; the previous record for rainfall in one month (July year unknown) was 245 mm.

For the prairies, the summer (June 1 to August 31) ranked as the second wettest (45% above average)and the 13th coolest (-0.5 C cooler than average) when compared with the 58-year period 1948 to2005.

The procedures used in 2005 remained the same as for the previous nine years. Three speciallyequipped cloud seeding aircraft were dedicated to the project. One Piper Cheyenne II was based inCalgary and a second Cheyenne II was based in Red Deer. A C340 was also based in Calgary. TheCalgary office and aircraft were located at the ESSO Avitat Flight Center at the Calgary International

Airport. A WMI Red Deer office was set up in the AvTech Flight Center that houses Hillman Air at the


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Red Deer Regional Airport. The operations center and ground weather radar was housed at the Old-Didsbury Airport.The aircraft and crews provided 24-hr service, seven days a week throughout the period. Nine pilotsand four meteorologists were assigned to the project this year, allowing everyone to follow a workschedule and receive scheduled time-off during the summer. There were no changes to the staff duringthe summer. Overall, the personnel and equipment performed exceptionally well and there were nointerruptions or missed opportunities in the service.

The TITAN radar images were sent to the WMI web server at 5-min intervals, although there were oftenmissing images in the web archive which were blamed on computer problems and interruptions in themicrowave internet connection at the radar. A more reliable radar file transfer routine will beinvestigated for the future. The radar performed very well and there was only one interruption betweenthe evening of August 30 and the morning of September 2 when the high voltage power supply failedand its replacement had to be shipped from Fargo. Fortunately, no thunderstorms occurred during thisperiod and there was no impact on our operations. High speed Internet was once again installed for thepilots in Calgary and Red Deer so that they could closely monitor the storm evolution and motion. Thisgave the pilots better knowledge of the storm situation they were going to encounter when they werelaunched.

Several public relations activities occurred this year. On June 16th, Gerald Pilger, Editor for CountryGuide magazine interviewed Jim Renick and Terry Krauss for an article that appeared in the magazine

later in the summer. On June 19

th

a film crew from CBC for the Nature of Things visited the radar torecord some film to support a story on the radiosonde releases conducted during the previous twosummers in support of GPS water vapor research conducted by the University of Calgary. On July 22ndCKFM radio from Olds interviewed Terry Krauss. On July 29th the Olds Gazette interviewed TerryKrauss. On July 30ththe Red Deer Advocate ran a front-page story about the hail suppression projectwhich was very favorable. All of the publicity was positive this year.

Agricultural crop damage statistics are available back to 1938. The full historical record was analyzedto see if there were statistical differences between 1938 to 1995, compared with the WMI seedingperiod from 1996 to 2005. Eight of the last ten years have loss-to-risk values below the historical trendline. The 2005 hail season had the third lowest loss-to-risk ratio in the last 28 years. There is a positiveassociation between the WMI cloud seeding period and a reduction in the Provincial hail damage. Thereduction in the 1996-2005 average compared with the previous ten years (1986-1995) is 19.6%.

Assuming annual crop losses of $100 million due to the historical trend of losses, the reduction of haildamage corresponds to an estimated accumulated benefit of $196 million to agriculture in the last tenyears.

In Alberta, property and casualty insurance companies paid out more than $1 Billion over the period1987 to 1995, averaging $113.2 Million per year. For the 7-year period 1996 to 2002, insurancecompanies paid approximately $452.6 Million, for an annual average of $64.7 Million, 43% less than theprevious 9-year average. This represents an average annual savings of $48.5 Million, totaling $485Million over 10 years. These averages will likely change slightly due to the severe hailstorm andflooding that struck Edmonton in 2004 (estimated damage $170 Million) and the severe storm thatstruck Medicine Hat on June 17th, 2005. The total estimated savings would likely be closer to $400Million after all the data is included up to 2005. These data do not represent statistical proof that theseeding works, however, there is an association between the cloud seeding and a reduction in propertydamage due to severe storms in Alberta.

All of the projects radar data, meteorological data, and reports have been recorded onto CD-ROM forthe Alberta Severe Weather Management Society. These data include the daily reports, radar maps,aircraft flight tracks, as well as meteorological charts for each day. These data can be made availablefor outside research purposes through a special request to the Alberta Severe Weather ManagementSociety.


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ACKNOWLEDGMENTS

WMI wishes to acknowledge the kind support of Robin Seacombe (President), Jim Renick (ProjectDirector), Catherine Janssen (Chief Financial Officer), and the entire Board of Directors of the AlbertaSevere Weather Management Society (ASWMS). The continued understanding, support, andcooperation of the ASWMS are greatly appreciated.

A number of agencies and people deserve recognition and thanks. The cooperation of Mark McCrae

and John Exley of the Air Traffic Control (ATC) Nav-Canada facilities at Calgary and Edmonton isgratefully acknowledged. The excellent cooperation by the ATC once again, played a very importantrole in allowing the project pilots to treat the threatening storms in an efficient and timely manner asrequired, often directly over the city of Calgary.

Dr. Sid Selirio, Senior Manager with the Agriculture Financial Services Corp. in Lacombe is thanked forproviding the crop insurance information. Once again, special thanks also goes to Bob Jackson forsharing his office and hangar at the Olds-Didsbury airport, used for the radar and communicationscontrol center. The cooperation of all these people helped make the project a success and much moreenjoyable.

WMI wishes to acknowledge the contributions of the staff who served the project during the summer of2005: meteorologists (Jason Goehring, Bill Shaw, Dr. Andre Sinkevich), electronics technicians (Barry

and Jeff Robinson), pilots in command (Ben Hiebert, Porter Janovsky, Gavin Lange, Mac McQuarrie,and Rex Watson); the co-pilots (Mark Friel, Craig Lee, Joel Zimmer, and Trevor Edwards), and theaircraft maintenance engineers (Gary Hillman and Dale Campbell). The staff performed exceptionallywell as a team. The support of Patrick and James Sweeney, Randy Jenson, Hans Ahlness, Bruce Boe,Dennis Afseth, Adam Lund, Cindy Dobbs, Deanne Dostal, Erin Fischer, and Vance Emerson in theFargo head office is also gratefully acknowledged. As always, the author wishes to thank Jim Renickfor his continued dedication, cooperation, support, and guidance during the field operations as well ashis contributions to this final report.


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Figure 1: Robin Seacombe (President ASWMS) and Jim Renick (Project Director).

Figure 2: Catherine Jenssen (CFO ASWMS) and Jim Sweeney (WMI Vice President).


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Figure 3: Bruce Boe (WMI Director of Meteorology) and Dr. Terry Krauss (WMI VP Meteorology and Project

Manager).

Figure 4: Meteorologists Bill Shaw and Dr. Andre Sinkevich.


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Figure 5: Jason Goehring (Meteorologist) and Jeff Robinson (Electronics Tech).

Figure 6: Gavin Lange (Chief Pilot) Gary Hillman (Aircraft Engineer).


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Figure 7: Pilots: Mac McQuarrie and Porter Janovsky.

Figure 8: Pilots: Rex Watson and Ben Hiebert.


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Figure 9: Pilots: Joel Zimmer and Craig Lee.

Figure 10: Pilots: Mark Friel and Trevor Edwards.


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TABLE OF CONTENTS

EXECUTIVE SUMMARY...............................................................................................................................3

LIST OF FIGURES......................................................................................................................................13

LIST OF TABLES .......................................................................................................................................15

INTRODUCTION .........................................................................................................................................16

THE 2005 FIELD PROGRAM .....................................................................................................................17

PRIORITIES................................................................................................................................................19

CONCEPTUAL HAIL MODEL ....................................................................................................................20

HAIL SUPPRESSION HYPOTHESIS ...............................................................................................................20 PRECIPITATION EFFICIENCY .......................................................................................................................22

CLARIFICATION OF CLOUD SEEDING GUIDELINES ............................................................................23

ONSET OF SEEDING...................................................................................................................................23 IDENTIFICATION OF HAIL PRODUCING STORMS ............................................................................................23

CLOUD SEEDING METHODOLOGY ...............................................................................................................24 NIGHT TIME SEEDING ................................................................................................................................25 STOPPING SEEDING ...................................................................................................................................25 SEEDING RATES ........................................................................................................................................25 SEEDING MATERIALS .................................................................................................................................26 FLARE EFFECTIVENESS TESTS ...................................................................................................................27

Summary of CSU Tests ......................................................................................................................29

PROGRAM ELEMENTS AND INFRASTRUCTURE..................................................................................30

GROUND SCHOOL ....................................................................................................................................31

PUBLIC RELATIONS .................................................................................................................................31

FLIGHT OPERATIONS...............................................................................................................................31

AIR-TRAFFIC CONTROL..............................................................................................................................31 CLOUD SEEDINGAIRCRAFT........................................................................................................................32

Piper Cheyenne II ...............................................................................................................................32C340A Aircraft.....................................................................................................................................34Meteorological Aircraft Instrumentation..............................................................................................34

RADAR CONTROL AND COMMUNICATIONS CENTER.........................................................................35

RADAR........................................................................................................................................................37

RADAR CALIBRATION CHECKS....................................................................................................................38

AIRCRAFT TRACKING GLOBAL POSITIONING SYSTEM (GPS)..........................................................40

SUMMARY OF SEEDING OPERATIONS..................................................................................................41

AIRCRAFT FLIGHTS ANDAMOUNT OF SEEDING ............................................................................................41 COMPARISON OF 2005WITH PREVIOUS YEARS ...........................................................................................43

STORM TRACK MAPS ..............................................................................................................................46

WEATHER FORECASTING .......................................................................................................................47

CONVECTIVE DAY CATEGORY (CDC) .........................................................................................................48COORDINATED UNIVERSAL TIME.................................................................................................................49


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DAILY BRIEFINGS.......................................................................................................................................49 METEOROLOGICAL STATISTICS...................................................................................................................49 FORECASTING PERFORMANCE ...................................................................................................................51 THE HAILCAST MODEL ...............................................................................................................................53 OBLAKO-2RUSSIAN CLOUD MODEL (BY DR.ANDRE SINKEVICH) .................................................................54

Model Input and Evaluation Data .......................................................................................................55Model Output Data..............................................................................................................................55

Assessment of Cloud Top Height Forecasts......................................................................................57

Assessment of Maximum Temperature Forecasts.............................................................................58Assessment of Dew Point Temperature Forecasts ............................................................................60Assessment of Thunderstorm Forecasts by Oblako-2 .......................................................................61Assessment of Hail forecasts by Oblako-2.........................................................................................61

JULY 19TH

, 2005: THE CALGARY STORM...............................................................................................62

METEOROLOGICAL SITUATION ....................................................................................................................62 SEEDING OPERATIONS...............................................................................................................................67

THE RELATIONSHIP BETWEEN THE MEDICINE HAT SEVERE HAILSTORM OF JUNE 17, 2005AND THE FLOODING IN SUNDRE ON JUNE 18, 2005 ...........................................................................69

HURRICANE KATRINA..............................................................................................................................77

CLIMATE PERSPECTIVES........................................................................................................................80

PRECIPITATION AT CALGARY AND RED DEER DURING THE SUMMER OF 2005 ................................................82PRECIPITATION AND TEMPERATUREANOMALIES IN CANADA DURING THE SUMMER OF 2005 ..........................84

PROVINCIAL CROP HAIL INSURANCE RESULTS.................................................................................85

INSURANCE BUREAU OF CANADA PROPERTY DAMAGE..................................................................88

CONCLUSIONS AND RECOMMENDATIONS..........................................................................................89

REFERENCES AND RECOMMENDED READING...................................................................................90

APPENDICES .............................................................................................................................................94

A. ORGANIZATIONCHART ..................................................................................................................95B. DAILYWEATHERANDACTIVITIESSUMMARYTABLE .................................................................96C.AIRCRAFTOPERATIONSFLIGHTSUMMARY2005.....................................................................127 D. FLIGHTSUMMARYTABLE2005....................................................................................................129 E. FORMS ............................................................................................................................................132F. SPECIFICATIONSFORPIPERCHEYENNEIIAIRCRAFT.............................................................136G. SPECIFICATIONSFORCESSNAC-340AIRCRAFT.....................................................................137H. GROUNDSCHOOLAGENDA.........................................................................................................138I. DAILYMETEOROLOGICAL FORECASTSTATISTICS2005 ..........................................................139J. PROJECTPERSONNELANDTELEPHONELIST ..........................................................................143


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LIST OF FIGURES

Figure 1: Robin Seacombe (President ASWMS) and Jim Renick (Project Director)................................................6

Figure 2: Catherine Jenssen (CFO ASWMS) and Jim Sweeney (WMI Vice President)............................................6

Figure 3: Bruce Boe (WMI Director of Meteorology) and Dr. Terry Krauss (WMI VP Meteorology and Project

Manager). ...................................................................................................................................................................7

Figure 4: Meteorologists Bill Shaw and Dr. Andre Sinkevich. .................................................................................7

Figure 5: Jason Goehring (Meteorologist) and Jeff Robinson (Electronics Tech). ..................................................8

Figure 6: Gavin Lange (Chief Pilot) Gary Hillman (Aircraft Engineer). .................................................................8Figure 7: Pilots: Mac McQuarrie and Porter Janovsky. ..........................................................................................9

Figure 8: Pilots: Rex Watson and Ben Hiebert. ........................................................................................................9

Figure 9: Pilots: Joel Zimmer and Craig Lee. ........................................................................................................10

Figure 10: Pilots: Mark Friel and Trevor Edwards................................................................................................10

Figure 11: The average number of hail days per year, based on the 19511980 climate normals of Environment

Canada (1987) and taken from Etkin and Brun (1999). ...........................................................................................16

Figure 12: Map of southern Alberta showing the project area and the radar location at the Olds-Didsbury

airport. Figure courtesy Steve Fick, Canadian Geographic (Shermata, 1998). .....................................................18

Figure 13: The conceptual model of hailstone formation and hail mitigation processes for Alberta (adapted from

WMO, 1995). This schematic figure shows the cloud seeding methodology at cloud-top and cloud-base for a

mature hailstorm.......................................................................................................................................................21

Figure 14: A three-dimensional schematic figure of an Alberta hailstorm, showing the cloud seeding

methodology within the new growth zone.................................................................................................................22Figure 15: Precipitation efficiency for High Plains convective storms. Known supercell hailstorms are labeled S.

Storms that produced rain only are labeled R (Browning, 1977). ...........................................................................23

Figure 16: A photo of a cloud seeding plane dropping ejectable flares during a cloud seeding penetration (photo

courtesy John Ulan)..................................................................................................................................................25

Figure 17: Pilots Craig Lee and Rex Watson attaching the ejectable flare racks on the belly of a Cheyenne

seeding aircraft.........................................................................................................................................................27

Figure 18: Hail Stop 2, C340 aircraft shown seeding with Acetone Solution burners and Burn-In-Place (BIP)

flares. ........................................................................................................................................................................27

Figure 19: Yield of ice crystals (corrected) per gram of pyrotechnic versus cloud supercooling temperature

(T


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Figure 33: The frequency of occurrence and cumulative distributions of aircraft take-off and landing times for all

flights from 2000 to 2005..........................................................................................................................................42

Figure 34: Amount of AgI dispensed per operational day in 2005. ........................................................................43

Figure 35: Map of all hailstorm tracks during 2005 (courtesy of Jim Renick).......................................................46

Figure 36: Map of all hailstorm tracks during the five-year period 2001-2005 (courtesy of Jim Renick). ............47

Figure 37: The frequency distribution of the difference of cloud top height predicted by the model and observed

by the radar. .............................................................................................................................................................57

Figure 38: The frequency distribution of the difference of Observed Maximum Temperature in Calgary and the

Forecast Max Temperature. .....................................................................................................................................58Figure 39: The frequency distribution of the difference of Observed Maximum Temperature in Red Deer and the

Forecast Max Temperature. .....................................................................................................................................59

Figure 40: The frequency distribution of the difference of Observed Maximum Dew Point Temperature in

Calgary and the Forecast Max Dew Point Temperature. ........................................................................................60

Figure 41: The frequency distribution of the difference of Observed Maximum Dew Point Temperature in Red

Deer and the Forecast Max Dew Point Temperature...............................................................................................61

Figure 42: Maximum Reflectivity map for the storms on 19-July-2005..................................................................63

Figure 43: Aircraft tracks for Hailstop 1, 2, and 3 on 19-July-2005......................................................................63

Figure 44: GEM model 12 hr forecast of 500 mb heights and vorticity at 6 pm 19-July-2005 (00Z, 20 July 2005).

..................................................................................................................................................................................64

Figure 45: Jet stream analysis at 7 pm 19-July-2005 (01Z, 20 July 2005).............................................................64

Figure 46: Surface analysis at 6 pm (00Z) with IR satellite image at 7:44 pm (0144Z 20 July 2005). ..................65

Figure 47: ETA 12 hr forecast atmospheric sounding for Calgary at 6 pm (00UTC) on July 19th2005. Alsoshown is the trace for a lifted parcel with Temperature 19C and Dew Point 13C as reported in Calgary at 5 pm.65

Figure 48: Map of surface 3-hr pressure changes and wind vectors at 3 pm (21Z) on July 19th, 2005. ...............66

Figure 49: Map of surface streamlines and equivalent potential temperature (Theta-E) at 3 pm (21Z) on July

19th, 2005. ................................................................................................................................................................66

Figure 50: Surface moisture-flux divergence and wind gust map at 21Z (3 pm) on July 19th, 2005. ....................67

Figure 51: The radar composite image at 6:31pm (0031Z) on July 19th, 2005 showing storms along the foothills

and one storm north of Cochrane moving towards Calgary. The radar echo over Calgary was reported to be a

moderate rain shower at the time. The track of HS1 (green) is shown. The cell top heights (km) are indicated...68

Figure 52: The radar composite image at 6:45 pm (0045Z) on July 19th, 2005 showing two storms along the

foothills north of Cochrane moving towards Calgary. HS2 was launched to seed these storms. The radar echo

over Calgary had developed quickly into a hailstorm and the seeding track of HS1 (green) is shown. The cell top

heights (km) are indicated. .......................................................................................................................................68

Figure 53: GEM 4-panel weather chart valid for 6 pm Friday 17-June-2005 (00UTC 18-June-2005).................69Figure 54: GEM 4-panel weather chart valid for 6 pm Saturday, 18-June-2005 (00UTC 19-June-2005). ...........70

Figure 55: 250 mb (10.4 km altitude) chart valid for 6 pm, Friday 17-June-2005.................................................71

Figure 56: 500 mb (5.5 km altitude) chart valid for 6 pm, Friday 17-June-2005...................................................71

Figure 57: The surface streamlines and equivalent potential temperature chart at 4 pm (22 UTC), 17 June 2005.

..................................................................................................................................................................................72

Figure 58: The radar display at 2:30 pm (2030 UTC) 17 June 2005 from the Environment Canada radar located

at Schuler, Alberta....................................................................................................................................................73

Figure 59: The radar display at 3:00 pm (2100 UTC) 17 June 2005 from the Environment Canada radar at

Schuler, Alberta........................................................................................................................................................73

Figure 60: The radar display at 5:40 pm (2340UTC) 17 June 2005 from the Environment Canada radar located

at Schuler, Alberta. At this time there was a severe thunderstorm just east of Medicine Hat. ................................74

Figure 61: The visible satellite photo at 4:15 pm (2215 UTC) on 17 June 2005....................................................75

Figure 62: Current surface weather and dew point chart at 9 pm 17 June 2005 (03 UTC 18 June). ....................76Figure 63: Current surface weather and dew point chart at 8 am 18 June 2005 (14 UTC). ..................................76

Figure 64: The track of Hurricane Katrina between August 23rd and 30th, 2005.................................................78

Figure 65: A IR satellite image of hurricane Katrina at the time of landfall (12 UTC, 29-Aug-2005)...................78

Figure 66: Composite IR satellite image and surface analysis at 2230Z on 28-August-2005. ...............................79

Figure 67: ETA model 24 hr forecasted 500 mb chart valid at 12Z on 29-August-2005........................................79

Figure 68: Pacific Ocean sea surface temperatures and temperature anomalies for the period August 2002 to

July 2005. .................................................................................................................................................................81

Figure 69: SST temperature anomalies for the 4 Nino regions of the equatorial tropical Pacific over the period

1986 to 2005. ............................................................................................................................................................82

Figure 70: Daily and accumulated rainfall for Calgary from June 1 to August 31, 2005......................................83


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Figure 71: Daily and accumulated rainfall for Red Deer from June 1 to August 31, 2005....................................83

Figure 72: Departures from normal Precipitation during the summer of 2005 in Canada....................................84

Figure 73: Departures from normal Temperature during the summer of 2005 in Canada. ...................................85

Figure 74: Alberta Agriculture Financial Services Corp hail insurance loss-to-risk and claims statistics from

1978 to 2004. ............................................................................................................................................................86

Figure 75: Statistical summary of loss-to-risk values from 1938 to 1995...............................................................87

Figure 76: Statistical summary of loss-to-risk values from 1996 to 2005...............................................................87

Figure 77: Property damage due to natural disasters in Alberta and for the all of Canada (Insurance Bureau of

Canada Facts Book, 2004). ......................................................................................................................................88

LIST OF TABLES

Table 1: Census figures for the towns and cities in the project area. .....................................................................19

Table 2: Yield results of ICE flares. ........................................................................................................................28

Table 3: Rate Data (LWC = 1.5 g m-3 points are average values).........................................................................29

Table 4: Radar parameter calibration values for the ALBERTA-WMI WR100. .....................................................39

Table 5: Radar transmitted power calibration values measured during the 2005 season. .....................................39

Table 6: Operational Statistics for 1996 to 2005. ...................................................................................................44

Table 7: Cloud seeding flare usage comparison by aircraft. ..................................................................................45

Table 8: Description of Convective Day Category (CDC) Index ............................................................................48

Table 9: Summary of daily atmospheric parameters used as inputs for the daily forecast the CDC during 2005. 49

Table 10: Summary of daily forecast atmospheric parameters on hail days during 2005......................................50Table 11: Table of the Observed versus Forecast days with Hail and No-Hail for the summer of 2005................52

Table 12: Table of Forecast versus Observed CDC daily values 2005. ..................................................................52

Table 13: Annual Summary of Convective Day Categories (CDC). .......................................................................53

Table 14: Table of Forecast versus Observed CDC daily values using HAILSCAST during the summer of 2005.54

Table 15: Probability of detection (POD), false alarm ratio (FAR), and critical success index (CSI) performance

of HAILCAST and WMI from 2002 to 2005. ............................................................................................................54

Table 16: Statistical summary of the difference between cloud top height predicted by the Obloko-2 model Htopm

(km) and observed by the radar Htopr (km). ............................................................................................................58

Table 17: Statistical summary of the difference between T-measured max temperature in Calgary and Tpr-

forecasted max temperature. ....................................................................................................................................59

Table 18: Statistical summary of the difference between T-measured max temperature in Red Deer and Tpr

forecast max temperature. ........................................................................................................................................59

Table 19: Statistical summary of the difference between the measured max dew point temperature in Calgary andthe forecasted max dew point temperature...............................................................................................................60

Table 20: Statistical summary of the difference between the measured max dew point temperature in Red Deer

and the forecasted max dew point temperature........................................................................................................61


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INTRODUCTION

Hailstorms pose a serious threat to property and crops in the province of Alberta. Historically, claims foragricultural hail damage are received on an average of 50 days each year between 1 June and 10September (Summers and Wojtiw, 1971). The most recent climatology of hail in Canada was publishedby Etkin and Brun (1999) in the International Journal of Climatology. The average number of hail daysper year, based on the 19511980 climate normals (Environment Canada, 1987) is shown in Figure 11.The contours were hand drawn, based primarily upon about 350 weather stations. The highest

frequency of hail in Canada occurs in Alberta between the North Saskatchewan River and the BowRiver, immediately downwind of the Rocky Mountain foothills. This region is often referred to as hailalley.

Figure 11: The average number of hail days per year, based on the 19511980 climate normals ofEnvironment Canada (1987) and taken from Etkin and Brun (1999).

Etkin and Brun (1999) point out that the period 19771993 was associated with substantial increases inhail-observing stations. As the 19511980 hail climatology was mostly based on pre-1977 data, it had arelatively coarse resolution in comparison. An updated Alberta hail climatology for 19771993 hassince been completed. It has a greater resolution than the national climatology, and shows the


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importance of some topographical features, such as the Rocky Mountains. The influence of localtopographical features on mesoscale hail frequency is a major control. After 1982, hail frequencies in

Alberta showed a significant increase. The City of Calgary is in a region that normally gets between 3and 4 hailstorms each year.

By overlaying the hail frequency map with the population density map, the region of greatest financialrisk to insurance companies covers the area from Calgary to Red Deer and Rocky Mountain House.For this reason, this is the region that was selected as the target area for the hail suppression program.

Insurance claims due to hailstorms in urban areas worldwide have generally escalated over the past 10years. Denver Colorado was pounded by golf-ball to tennis-ball sized hail on July 11, 1990, anddamages reached a record (for the U.S.A. at that time) $625 million. In Canada, the damagesassociated with the severe hailstorm that struck Calgary on September 7, 1991 exceeded $416 million(Insurance Bureau of Canada, 2004). Insured claims from the hailstorm that struck Sydney Australia on

April 14, 1999 were approximately $1.5 billion, making it the most damaging event in Australianinsurance history. A study by Herzog (2002) compiled and summarized the hailstorm damages in theUSA for the period 1994-2000 for the Institute for Business and Home Safety (IBHS). Verified haillosses amounted to $2.5 Billion per year, with the actual amount possibly being 50% higher. Personalbuilding losses totalled $11.5 Billion (66%), commercial building losses totalled $2.7B (15%), andvehicles accounted for $3.3B (19%). And recently, the most damaging hailstorm ever recorded in theUSA moved from eastern Kansas to southern Illinois on 10 April 2001, depositing 2.5- to 7.5-cm-

diameter hailstones along a 585-km path, over portions of the St. Louis and Kansas City urban areascollectively created $1.9 billion in damage claims from a 2-day period, becoming the ninth most costlyweather catastrophe in the United States since property insurance records began in 1949 (Changnonand Burroughs, 2003).

Estimates of the average annual crop loss to hail have also continued to increase with time, from $50million annually in 1975 (Renick, 1975) to more than $150 million annually during the period 1980 -1985 (Alberta Research Council, 1986). Actual insured crop losses are typically in the $80M rangeannually.

The new Alberta Hail Suppression Project was initiated in 1996 as a result of the increased frequency ofdamaging hailstorms in Alberta, compounded by an increasing population inside an area of high stormfrequency. It is the first project of its kind in the World to be entirely funded by private insurancecompanies with the sole objective of reducing the damage to property by hail. At this time, Alberta CropInsurance and the Provincial and Federal Governments do not contribute financially to the project,although they stand to benefit from the seeding.

Weather Modification Inc. (WMI) has been a leader in the field of hail suppression since the early1960's. With extensive knowledge and experience in the cloud seeding industry, WMI is best known forits successful hail suppression operations in the northern great plains and other cloud modificationservices around the world, most recently and notably in Argentina. WMI was awarded the first contractto conduct the Alberta Hail Suppression Project in April 1996 by the Alberta Severe WeatherManagement Society. The project was made an ongoing program of the Alberta insurance industry in2001 because of the drop in hail damage costs in Alberta, counter to the trend in the rest of the countryand the World. The contract calls for the provision of all personnel and equipment for a turnkey systemof cloud seeding and related services for the purpose of reducing hail damage to property insouth-central (Calgary to Red Deer) Alberta. The organization chart of the project is shown in Appendix

A.

THE 2005 FIELD PROGRAM

In 2005, WMI conducted the operational cloud-seeding program from June 1st to September 15th. Theproject is based upon the techniques, methods, and results of the long-term hail research projectconducted by the Alberta Research Council from the late 1960s through 1985 (Alberta ResearchCouncil, 1986) and by WMI in North Dakota (Smith et al, 1997). The present program utilizes the latestcloud seeding technology available, incorporating several notable improvements over previous projectsin the province. These improvements include:


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New fast-acting, high-yield mixtures for the silver-iodide flares and acetone solution. The flares aremanufactured by Ice Crystal Engineering (ICE) of North Dakota. The new generation ICEpyrotechnics produce >1011ice nuclei per gram of AgI at -4C, and produce between 10 13and 1014ice nuclei per gram of pyrotechnic between -6C and -10C. CSU isothermal cloud chamber testsindicate that at a temperature of -6.3C, 63% of the nuclei are active in


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PROJECT OBJECTIVES

The project has two main objectives:

Conduct cloud seeding using 3 aircraft with experienced crews to suppress hail for the purpose ofreducing damage to property;

Operate a C-band weather radar and collect weather information by skilled professionalmeteorologists and engineers for purposes of storm identification, accurate storm tracking, optimaldirection of aircraft to conduct cloud seeding for hail suppression purposes, and the collection of adata archive that may be used for the scientific assessment of the program's effectiveness.

Priorities

Table 1 lists the recent census figures obtained via the internet for the cities and towns within theproject area. Priority is given according to population, which is related to the risk of property damage.This list was posted in the radar control room as a constant reminder to the meteorologists of the prioritywhen allocating resources to storms on any given day. The biggest increase in population recently hasoccurred in Cochrane, Airdrie, Sylvan Lake, and Okotoks. Project meteorologists made special note ofthe fact that the combined population of Turner Valley and Black Diamond is almost as large asBlackfalds or Didsbury. Storms that do not threaten a town or city are not likely to be seeded. Also,most storms are no longer seeded after they cross Highway 2, except for storms east of Airdrie and

Calgary that might threaten Strathmore.

Table 1: Census figures for the towns and cities in the project area.

Rank POPULATION 1996 2001 2003+ Increase%

1 Calgary Metropolitan Area 821,628 951,395 953,000 16%

2 Calgary 768,000 879,277 933,495 22%

3 Red Deer 60,000 67,707 72,691 21%

4 Airdrie 15,900 20,382 23,680 49%

5 Cochrane 7,400 11,798 12,074 63%

6 Okotoks 8,510 11,664 11,664 37%

7 Lacombe 9,384 9,946 6%

8 High River 7,400 9,345 9,345 26%

9 Strathmore 7,621 8,640 13%

10 Sylvan Lake 5,200 7,884 7,493 44%

11 Innisfail 6,100 6,954 6,958 14%

12 Olds 5,800 6,607 6,607 14%

13 Rocky Mountain House 5,800 6,208 6,208 7%

14 Didsbury 3,600 3,932 3,932 9%

15 Blackfalds 3,042 3,812 25%

16 Turner Valley/Black Diamond 3,474

17 Crossfield 1,900 2,389 2,288 20%

18 Sundre 2,000 2,267 2,267 13%

19 Carstairs 1,900 2,254 2,254 19%20 Penhold 1,625 1,729 1,729 6%

21 Bowden 1,000 1,174 17%

22 Irricana 820 1,038 1,043 27%

23 Eckville 900 1,019 13%

24 Caroline 470 556 18%

25 Cremona 380 415 9%


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CONCEPTUAL HAIL MODEL

The hail suppression conceptual model is based on the experience of WMI in the USA, Canada,Argentina, and Greece. It involves the use of silver-iodide reagents to seed the developing feederclouds near the -10C level in the upshear, new growth propagation region of hailstorms. The silver-iodide reagents initiate a condensation-freezing process and produce enhanced concentrations of icecrystals that compete for the available, super-cooled liquid water in a storm and help prevent the growthof large damaging hail. The seeding also initiates the precipitation process earlier in a cloud (cell) to

speed up the growth of cloud hydrometeors via an ice-phase (graupel) to rain mechanism instead ofcontinuing to grow to damaging hail.

Hail Suppression Hypothesis

The cloud seeding hypothesis is based on the cloud microphysical concept of "beneficial competition".Beneficial competition is based upon the documented deficiency of natural ice nuclei in the environmentand that the injection of silver iodide (AgI) will result in the production of a significant number of"artificial" ice nuclei. The natural and artificial ice crystals "compete" for the available super-cooledliquid cloud water within the storm. Hence, the hailstones that are formed within the seeded cloudvolumes will be smaller and produce less damage if they should survive the fall to the surface. Ifsufficient nuclei are introduced into the new growth region of the storm, then the hailstones will be smallenough to melt completely before reaching the ground. Cloud seeding alters the microphysics of the

treated clouds, assuming that the present precipitation process is inefficient due to a deficiency ofnatural ice nuclei. This deficiency of natural ice has been documented in the new growth zone of

Alberta storms (Krauss, 1981). Cloud seeding does not attempt to compete directly with the energy anddynamics of the storm. Any alteration of the storm dynamics occurs as a consequence of the increasedice crystal concentration and initiation of riming and precipitation sized ice particles earlier in the cloudslifetime.

The cloud seeding is based on the conceptual model of Alberta hailstorms which evolved from theexperiments and studies of Chisholm (1970), Chisholm and Renick (1972), Marwitz (1972a,b,c), Bargeand Bergwall (1976), Krauss and Marwitz (1984), and English (1986). Direct observational evidencefrom the instrumented aircraft penetrations of Colorado and Alberta storms in the 1970's and early1980s indicates that hail embryos grow within the time evolving "main" updraft of single cell storms andwithin the updrafts of developing "feeder clouds" or cumulus towers that flank mature "multi-cell" and

"super-cell" storms (see e.g. Foote, 1984; Krauss and Marwitz, 1984). The computation of hail growthtrajectories within the context of measured storm wind fields provided a powerful new tool for integratingcertain parts of hail growth theories, and illustrated a striking complexity in the hail growth process.Some of this complexity is reviewed in the paper of Foote (1985) that classifies a broad spectrum ofstorm types according to both dynamical and microphysical processes thought to be critical to hailproduction. Hail embryo sources identified by Foote (1985) include the following:

Embryos from first-ice in a time-developing updraft Embryos from first-ice in the core of a long-lived updraft Embryos from flanking cumulus congestus Embryos from a merging mature cell Embryos from a mature cell positioned upwind Embryos from the edges of the main updraft

Embryos created by melting and shedding Embryos from entrainment of stratiform cloud Embryos from embedded small-scale updrafts and downdrafts Recirculation of embryos that have made a first pass through the updraft core

The growth to large hail is hypothesized to occur primarily along the edges of the main storm updraftwhere the merging feeder clouds interact with the main storm updraft (WMO, 1995). The maturehailstorm may consist of complicated airflow patterns and particle trajectories; therefore, the cloud-seeding cannot hope to affect all embryo sources but attempts to modify the primary hail formationprocess. In other words, the cloud seeding cannot attempt to eliminate all of the hail, but canreduce the size and amount of hail.


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Studies of the internal structure of large hailstones in Alberta and elsewhere have shown that hailstonescan have either a graupel hail embryo or a frozen drop hail embryo. The different hail embryos indicatedifferent growth histories and trajectories and illustrate the complexity within a single hailstorm. Thepresent seeding methodology attempts to compete with the graupel embryo process. Drop hailembryos are thought to originate from secondary sources (shedding from large existing hail stones, orvia a recirculation process at the edge of the main updraft). The seeding can only reduce the hail withdrop embryos if the liquid water can be reduced to limit their growth, or if the dynamics of the storm canbe affected to eliminate the recirculation processes that formed the drop embryo in the first place.

A schematic diagram of the conceptual storm model showing the hail origin and growth processeswithin a severe Alberta hailstorm is shown in Figure 13. A three-dimensional schematic figure of an

Alberta hailstorm is shown in Figure 14, showing the cloud seeding methodology in the new growthzone.

Figure 13: The conceptual model of hailstone formation and hail mitigation processes for Alberta (adaptedfrom WMO, 1995). This schematic figure shows the cloud seeding methodology at cloud-top and cloud-

base for a mature hailstorm.


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Figure 14: A three-dimensional schematic figure of an Alberta hailstorm, showing the cloud seedingmethodology within the new growth zone.

As mentioned previously, cloud seeding cannot prevent or completely eliminate the occurrence ofdamaging hail. We presently do not have the ability to predict with any certainty exactly the amount andsize of hail that would occur if cloud seeding did not take place. Therefore, we do not have the ability topredict with certainty the net effect of the seeding. Our purpose is to seed the new growth zone ofhailstorms and observe the amount and type of precipitation at the surface, as well as the radarreflectivity characteristics of the storm before, during, and after seeding. We expect that the successfulapplication of the technology will yield a decrease of damaging hail by approximately 50% of theamount that would have occurred if seeding had not taken place. This goal is consistent with the results

reported in North Dakota (Smith et al, 1997) and in Greece (Rudolph et al, 1994). The decrease in hailcan only be measured as an average over time (e.g. 5 years) and over an area and then compared withthe historical values for the same areas. Because of these uncertainties, the evaluation of any hailmitigation program requires a statistical analysis. Both seeded storms and unseeded storms havevariability and populations of seeded and unseeded storms overlap in all measurements of theircharacteristics.

Precipitation Efficiency

A common question about cloud seeding concerns the effect on the rainfall. There is a general (yetfalse) assumption by the public and some scientists that thunderstorms operate at near 100% efficiencyin producing rainfall, therefore, any modification of the hail, or causing the rainfall to start earlier, maylimit the amount of precipitation that can fall later in a storms lifetime, down wind of the project area.There have been numerous studies of the fluxes of air and water vapor through convective clouds andthese are summarized in Figure 15.

Precipitation efficiencies can vary widely from as little as 2% for storms studied by Marwitz (1972) andDennis et al. (1970) to near 100%. Marwitz (1972) and Foote and Fankhauser (1973) show that in thecase of High Plains storms there is an inverse relation between the precipitation efficiency and theenvironmental wind shear in the cloud-bearing layer. The least efficient storms tend to be supercellhailstorms; the highly efficient storms tend not to produce hail. The average wind shear on hail days in

Alberta is approximately 2.5 x 10-3

sec-1

. This shear value corresponds to precipitation efficiency near50%.


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It is logical that the production of large, damaging hail is a result of the natural inefficiency of the stormto produce rain. Therefore, the introduction of more precipitation embryos earlier in a clouds lifetime ishighly advantageous to the initiation of precipitation earlier, making the cloud more efficient as a rainproducer, and in the process reducing the amount and size of the hail. Increasing the rainfall from ahailstorm by 20% due to the seeding is a very achievable goal, and means that less water is lost eithervia the entrainment of dry environmental air through the sides and top of the cloud, or water lost to icecrystals that are exhausted out of the anvil at the top of the troposphere and which eventually sublimateback to the vapor phase at high altitudes.

Figure 15: Precipitation efficiency for High Plains convective storms. Known supercell hailstorms are

labeled S. Storms that produced rain only are labeled R (Browning, 1977).

CLARIFICATION OF CLOUD SEEDING GUIDELINES

The following guidelines represent the current state of the science of hail suppression operations beingapplied by Weather Modification Inc.

Onset of Seeding

In order for cloud seeding to be successful, it is the goal of the program to seed (inject ice nucleatingagents) the developing "new growth" cloud towers of a hail producing storm, at least 20 minutes beforethe damaging hail falls over a town or city within the target zone. For the Alberta project, the principletargets are the towns and cities within the project area. Since 20 min is the minimum time reasonablyexpected for the seeding material to nucleate, and have the seeded ice crystals grow to sufficient size

to compete for the available super-cooled liquid water in order to yield positive results, a 30 min leadtime is generally thought to be advisable.

Identification of Hail Producing Storms

The height of the 45 dBZ contour was a criterion tested in the Swiss hail suppression program. TheSwiss research indicated that all hailstorms had 45 dBZ contours that exceeded the 5C temperaturelevel (Waldvogel, Federer, and Grimm, 1979). There was a False Alarm Rate (FAR) of 50%, largelybecause some strong rainstorms also met the criterion. However, it is preferable to make an error andassume that a heavy rainstorm is going to produce hail than to mistakenly believe that a hailstorm isonly going to produce heavy rain. Studies of Alberta hailstorms also indicated that 50% of all Alberta


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hail storms had a maximum radar reflectivity greater than 45 dBZ, higher than the -5C level(Humphries, English, and Renick, 1987). The Russian criteria for hail identification stated that theheight of the 45 dBZ contour had to exceed the height of the 0C isotherm by more than 2 km(Abshaev, 1999). Similarly, the criteria used by the National Hail Research Experiment in the USA1972-1974 for a declared hail day was defined by radar maximum reflectivity greater than 45 dBZ abovethe -5C level (Foote and Knight, 1979).

Our experience suggests that the Swiss/Alberta/Russian/USA criterion is reasonable (Makitov, 1999).

The physical reasoning behind it is simply that high radar reflectivity implies that significant supercooledliquid water exists at temperatures cold enough for large hail growth.

In Alberta, the TITAN cell identification program was set in 2005 to track any cell having >10 km3of 40

dBZ reflectivity, extending above 3 km altitude (MSL). Each cell tracked by TITAN was then consideredto be a potential hail threat; therefore, this represents our seeding criteria. A storm is a seedingcandidate if the storm cell (as defined by TITAN) is moving towards, and is expected to reach, a town orcity within the target area in less than 30 min.

Cloud Seeding Methodology

Radar meteorologists are responsible for making the "seed" decision and directing the cloud seedingmissions, incorporating the visual observations of the pilots into their decisions. Patrol flights are often

launched before clouds within the target area meet the radar reflectivity seeding criteria, especially overthe cities of Calgary and Red Deer. These patrol flights provide a quicker response to developing cells.In general, a patrol is launched in the event of visual reports of vigorous towering cumulus clouds orwhen radar cell tops exceed 25 kft height over the higher terrain along the western border on dayswhen the forecast calls for thunderstorms with large hail potential.

Launches of more than one aircraft are determined by the number of storms, the lead time required fora seeder aircraft to reach the proper location and altitude, and projected overlap of coverage andon-station time for multiple aircraft missions. In general, only one aircraft can work safely at cloud topand one aircraft at cloud base for a single storm. The operation of three aircraft is used to provideuninterrupted seeding coverage at either cloud-base or cloud-top and/or to seed three stormssimultaneously if required.

Factors that determine cloud top or cloud base seeding are: storm structure, visibility, cloud baseheight, or time available for aircraft to reach seeding altitude. Cloud base seeding is conducted byflying at cloud base within the main inflow of single cell storms, or the inflow associated with the newgrowth zone (shelf cloud) located on the upshear side of multi-cell storms.

Cloud top seeding can be conducted between -8C and -15C. The 20 g pencil flares fall approximately1.5 km (approximately 10C) during their 35-40 s burn time. Figure 16 shows a cloud seeding planedropping flares. The seeding aircraft penetrate the up-shear edges of single convective cells meetingthe seed criteria. For multi-cell storms, or storms with feeder clouds, the seeding aircraft penetrate thetops of the developing cumulus towers on the upshear sides of convective cells, as they grow upthrough the -10C flight level.


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Figure 16: A photo of a cloud seeding plane dropping ejectable flares during a cloud seeding penetration(photo courtesy John Ulan).

Night Time Seeding

Occasionally, with embedded cells or convective complexes at night, there are no clearly defined feederturrets visible to the flight crews or on radar. In these instances, a seeding aircraft will penetrate thestorm edge at an altitude between -5C and -10C, on the upshear side (region of tight radar reflectivitygradient) and seed by igniting an end-burner flare and injecting droppable pencil flares when updrafts

are encountered. If visibility is good below cloud base, nighttime seeding at base is also performed.Lightning can often help provide illumination at the cloud base.

Stopping Seeding

Strictly speaking, if the radar reflectivity criteria are met, seeding of all cells is to be continued.However, seeding is effective only within cloud updrafts and in the presence of super-cooled cloudwater, i.e. the developing, and mature stages in the evolution of the classic thunderstorm conceptualmodel. The dissipating stages of a storm should be seeded only if the maximum reflectivity isparticularly severe and there is evidence (visual cloud growth, or tight reflectivity gradients) indicatingthe possible presence of embedded updrafts. Storm cells being tracked by TITAN may not be seeded ifthere are no other indications of updraft or super-cooled liquid water, or if the storm does not threaten atown or city.

Seeding Rates

A seeding rate of one 20 g flare every 5 sec is typically used during cloud penetration. A higher rate isused (e.g. 1 flare every 2 to 3 sec) if updrafts are very strong (e.g. greater than 2000 ft/min) and thestorm is particularly intense. A cloud seeding pass is repeated immediately if there are visual signs ofnew cloud growth or if radar reflectivity gradients remain tight (indicative of persistent updrafts). If not, a5 to 10 min waiting period may be used, to allow for the seeding material to take effect and the storm todissipate, or for visual signs of glaciation to appear or radar reflectivity values to decrease and gradientsto weaken. This waiting period precludes the waste of seeding material and assures its optimumusage. Calculations show that the seeding rate of one flare every 5 sec will produce >1300 ice crystals


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per litre averaged over the plume within 2.5 min. This is more than sufficient to deplete the liquid watercontent produced by updrafts up to 10 m/s (2000 ft/min), thereby preventing the growth of hailstoneswithin the seeded cloud volumes (Cooper and Marwitz, 1980). For effective hail suppression, sufficientdispersion of the particles is required for the AgI plume from consecutive flares to overlap by the timethe cloud particles reach hail size. The work by Grandia et al. (1979) based on turbulencemeasurements within Alberta feeder clouds indicated that the time for the diameter of the diffusing lineof AgI to reach the integral length scale (200 m) in the inertial subrange size scales of mixing, is 140seconds. This is insufficient time for ice particles to grow to hail size, therefore, dropping flares at 5 sec

(assuming a true-airspeed of 80 m/s) intervals should provide sufficient nuclei and allow adequatedispersion to effectively deplete the super-cooled liquid water and prevent the growth of hail particles.The use of the 20 gm flares and a frequent drop rate provides better seeding coverage than using largerflares with a greater time/distance spacing between flare drops. In fact, the above calculations areconservative when one considers that the center of the ice crystal plume will have a greaterconcentration of ice crystals.

For cloud base seeding, a seeding rate using two acetone generators or one end-burner flare istypically used, dependent on the updraft velocity at the cloud base. For an updraft >500 ft/min,generators and consecutive flares per seeding run are typically used. Cloud seeding runs are repeateduntil no further inflow is found. Acetone burners are used to provide continuous silver iodide seeding ifextensive regions of weak updraft are found at cloud base and in the shelf cloud region. Base seedingis not conducted if downdrafts only are encountered at cloud base, since this would waste seeding

material.

Seeding Materials

WMI exclusively uses silver-iodide formulation flares manufactured by Ice Crystal Engineering (ICE) ofDavenport, ND. The ejectable flares contain 20 gm of seeding material and burn for approximately 37sec and fall approximately 4000 ft. The end-burning flares (BIP) contain 150 gm of seeding material,and burn for approximately 6 minutes.

Silver-iodide is dispensed using droppable/ejectable (shown in Figure 17) and/or end-burningpyrotechnics and/or acetone burners (shown in Figure 18). In 2005 the WMI acetone generatorsperformed very well and the level of required maintenance decreased significantly. Crews still kept aclose watch of igniter rods, valves, nozzles, and seals in order that the generators operated reliably.

Details of the silver-iodide acetone solution recipe used in 2005 are given in the Operations Manual.Arrangements were once again made with Solution Blend Services, a Calgary chemical company topre-mix the acetone seeding solution. All required handling, mixing, storage, and labelling requirementswere satisfied.


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Figure 17: Pilots Craig Lee and Rex Watson attaching the ejectable flare racks on the belly of a Cheyenneseeding aircraft.

Figure 18: Hail Stop 2, C340 aircraft shown seeding with Acetone Solution burners and Burn-In-Place (BIP)flares.

Flare Effectiveness Tests

The Cloud Simulation and Aerosol Laboratory at Colorado State University has performed routinetesting of the ice nucleating ability of aerosols produced from cloud seeding flares for many years(Garvey, 1975). Note: The CSU laboratory has now stopped this service and a new testing facility toconduct these standardized tests is desperately needed for the cloud seeding industry. The new ICEpyrotechnics were tested at CSU in 1999 and the results are reported in DeMott (1999). Aerosols werecollected and tested at nominal temperatures of -4, -6 and -10C. At least two tests at were done ateach temperature, with greater emphasis placed on warmer temperatures. Liquid water content (LWC)


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was 1.5 g m-3 in most tests, but was altered to 0.5 g m-3 in a few other experiments. In this way,information concerning the rate-dependence on cloud droplet concentration was obtained. The primaryproduct of the laboratory characterization is the "effectiveness plot" for the ice nucleant which gives thenumber of ice crystals formed per gram of nucleant as a function of cloud temperature. Yield results forthe ICE flares at various sets of conditions are shown in Figure 19 and are tabulated in Table 2.

1.00E+10

1.00E+11

1.00E+12

1.00E+13

1.00E+14

1.00E+15

0 5 10 15

Supercooling (C)

Yield(#g-1p

yro)

ICE Pyro

July 1999

______________________

Figure 19: Yield of ice crystals (corrected) per gram of pyrotechnic versus cloud supercooling temperature

(T


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y = 57.483x-1.9653

R2= 0.8298

y = 4.723x-1.1862

R2= 0.8552

0

1

2

3

4

5

67

8

9

10

0 2 4 6 8 10 12Supercooling (C)

Time(minutes

)

63

9

__________________

Figure 20: Times for 63% (diamond symbols) and 90% (square symbols) ice formation versus supercooling

(T


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The CSU isothermal cloud chamber tests indicate that, on a per gram basis of pyrotechnic, these valuesare comparable to the best product available worldwide in the pyrotechnic format. High yield and fastacting agents are important for hail suppression since the time-window of opportunity for successfulintervention of the hail growth process is often less than 10 minutes. More information about the ICEflares can be found on the internet at www.iceflares.com.

PROGRAM ELEMENTS AND INFRASTRUCTURE

A schematic diagram of the operational elements for the hail suppression project is shown in Figure 21.Details of the individual elements are described in more detail in the following sections.

The radiosonde (weather balloon) depicted in Figure 21 was part of the system on a limited during 2003and 2004. From those experiments we learned that the ETA/NAM model from the USA does anexcellent job in predicting the main features of the atmospheric profile for Calgary and Red Deer.

Although subtle details of inversion layers and moisture layers may not be resolved, the meteorologistshave generally sufficient information about the instability of the atmosphere to construct a goodforecast. One of the greatest gaps in our knowledge and data concerns the presence, absence, ortiming of trigger mechanisms for the onset of convection. The increasing availability of near real timesurface and satellite images via the internet is improving this situation. All meteorological informationwas received via the internet. WMI no longer needed a commercial agreement with EnvironmentCanada. In addition, temperature measurements from the aircraft cloud physics data system supplied

real time environmental data for the project meteorologists in some cases.

Figure 21: A schematic of the operational elements of the Alberta Hail Suppression Project.


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GROUND SCHOOL

A ground school was conducted for all project personnel on May 30th, 2005 in the training room atRoyal-Sun Alliance Insurance in Calgary prior to the commencement of the project field operations.Operational procedures, general conduct, and reporting requirements were presented and reviewed atthe ground school. Two representatives of NAV Canada in Calgary and Edmonton participated in theground school. Copies of the Ground School Program, as well as copies of the Flight Log and RadarLog forms are included in the Appendices. The ground school training topics included:

i. program overview and design, project area, target areas, and prioritiesii. overview of operations and proceduresiii. cloud seeding hypotheses for hail suppressioniv. cloud seeding theory and techniquesv. aviation weather problems and special proceduresvi. aircraft controlling techniques and proceduresvii. seeding aircraft equipment and characteristicsviii. weather radar equipment and basic principlesix. basic meteorological concepts and severe weather forecastingx. weather phenomena, fronts, and stormsxi. daily routines and proceduresxii. communications procedures

xiii. computers, documentation, and reporting proceduresxiv. safety, security precautions and procedures

PUBLIC RELATIONS

Several public relations activities occurred this year. On June 16th, Gerald Pilger, Editor for CountryGuide magazine interviewed Jim Renick and Terry Krauss for an article that appeared in the magazinelater in the summer. On June 19

tha film crew from CBC for the Nature of Things visited the radar to

record some film to support a story on the radiosonde releases conducted during the previous twosummers in support of GPS water vapor research conducted by the University of Calgary. On July 22

nd

CKFM radio from Olds interviewed Terry Krauss. On July 29th the Olds Gazette interviewed TerryKrauss. On July 30ththe Red Deer Advocate ran a front-page story about the hail suppression project,which was very favorable. All of the publicity was positive this year.

FLIGHT OPERATIONS

Three specially equipped cloud seeding aircraft were dedicated to the project. The aircraft and crewsprovided 24 hr coverage, seven days a week throughout the period. Two aircraft were stationed inCalgary and one aircraft in Red Deer. This permitted close proximity to storms and fast response tolaunch decisions. Delays in launching from Calgary were minimized thanks to the co-operation of Nav-Canada air traffic control in Calgary.

When convective clouds were detected by radar, the seeding aircraft were placed on standby status.Aircraft on standby status are able to launch and reach a target cloud within 60 min after the request tolaunch has been made by the controlling meteorologist. When seedable clouds are imminent, theseeding aircraft are placed on alert status. Aircraft on alert status are able to launch and reach a targetcloud within 25 min after the request to launch. Aircraft were available and prepared to commence aseeding mission at any time and the seeding of a storm often continued after darkness with due regardto safety.

Air-Traffic Control

Prior to the start of field operations, arrangements were made with NAV Canada managers of Air TrafficServices in Calgary and Edmonton to coordinate the cloud seeding aircraft operations. Permission wasgranted to file pre-defined flight plans for the project aircraft, with special designations and fixedtransponder codes. The designated aircraft were as follows: Hail-Stop 1 for the Cheyenne II airplane(N234K) based in Calgary, Hail-Stop 2 for the C340 aircraft (N123KK) based in Calgary, and Hail-Stop3 for the Cheyenne II aircraft (N232PS) stationed in Red Deer.


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Direct-line telephone numbers were used to notify air traffic controllers of cloud seeding launches.Aircraft were launched to a specific location identified by VOR and DME coordinates, or town. Distinctair traffic clearance was given to project aircraft within a 10 nautical mile radius of the specified stormlocation. Cloud top aircraft were given 2,000 ft clearances above their altitude and 7,000 ft below theiraltitude. Cloud base aircraft were given a +/- 1,000 ft altitude clearance. This procedure worked verywell in general. On a few occasions, seeding aircraft were asked to climb to a higher altitude over thecity of Calgary or to suspend seeding for a few minutes (


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full dual VFR/IFR instrumentation, pressurized cabin, and emergency oxygen. The Cheyenne II has fullde-ice equipment and is particularly well suited for flying in icing conditions for extended periods of time.These conditions are common at seeding altitudes within the thunderstorms of Alberta. The longermission times of this aircraft can provide coverage of the entire project area if required, allowingsignificant savings in aircraft, fuel and personnel costs. The added performance of the Cheyenne IImeans that it has sufficient power to climb safely above the dangerous icing zone (-10 C to -15C) ifrequired, or descend to lower and warmer altitudes to de-ice and quickly climb back up to cloud-topseeding altitude. It can also provide accurate measurements of cloud conditions and cloud

temperature. A third seat was provided for training or observing purposes. The major advantages ofthe Cheyenne II are as follows:

4 hour duration or more for longer seeding missions and better seeding coverage; lower Jet fuel price per liter; reserve power for severe icing conditions; exceptional speed for rapid response or ferry between target areas; and higher margin of safety;

The specifications of the Cheyenne II are given in an Appendix. All three aircraft were equipped withflare racks carrying 306 droppable flares containing 20 grams of AgI and also 28 end-burning flarescontaining 150 grams of AgI for seeding at cloud base. The Cheyenne II was also equipped with GPSnavigation system, onboard weather avoidance radar, and a VHF radio system for direct contact withoperational personnel at the communications and control center.

Figure 23: Piper Cheyenne II aircraft (N234K) designated as Hail-Stop 1 shown at the Calgary Airport.


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Figure 24: Piper Cheyenne II aircraft (N232PS) designated as Hail-Stop 3 shown at the Red Deer RegionalAirport.

C340A Aircraft

Cloud seeding was also conducted using one Cessna 340A aircraft equipped with ejectable flare bellyracks, wing mounted flare racks, and acetone burners. The aircraft registered as N123KK wasdesignated as Hail-Stop 2 (shown in Figure 25). The C340A aircraft is a pressurized, twin-engine, sixcylinder, turbocharged and fuel-injected all weather aircraft. The C340 aircraft also has a weatheravoidance radar and GPS navigation system. Complete specifications for the C340 are given in an

Appendix. The C340 aircraft carried 306 20-g pencil flares and 24 150-g end-burning flares and two 7US gallon acetone burners. Although the C340 can seed at cloud top, its performance is rather limitedin known icing conditions. Therefore, the C340 is used primarily as a cloud-base seeder. During 2005,the C340 was used exclusively as a cloud-base seeder and did not conduct any seeding at cloud top.

Meteorological Aircraft Instrumentation

Each of the cloud seeding aircraft had a temperature and liquid water sensor to help assure that thecloud penetration seeding runs were conducted at known temperature levels and to document thepresence of supercooled liquid cloud water. A radio telemetry system was used to transmit the aircraftdata to the radar communications and control center where it was displayed in real time and recorded at1 sec intervals. These measurements, combined with the recorded radar data, helped assure that theproject is conducted on a sound scientific basis.

All three aircraft performed very reliably with no seeding opportunities were missed due to maintenanceissues.


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Figure 25: C340A aircraft (N123KK) designated as Hail-Stop 2 and configured to seed with droppable

flares, end-burning flares, and AgI acetone burners.

RADAR CONTROL AND COMMUNICATIONS CENTER

The projects radar control room consists of the Airlink computer with radio telemetry modem for GPS

tracking information, as well as the TITAN computer and display, and the meteorological dataacquisition (Compaq) computer. Controllers communicated with the seeding aircraft using a VHF radioat 122.95 MHz frequency. The controlling duties were shared by Terry Krauss, Bill Shaw, AndreSinkevich, and Jason Goehring (shown in Figure 26).

An upgraded TITAN radar display and analysis computer system was installed last year (shown inFigure 27). The new TITAN was able to display several new hail parameters that gave themeteorologists additional information to improve identification of hailstorms and improved the directionof the aircraft to the most important hail growth regions of the storm. The TITAN radar images weresent to the WMI web server at 5-min intervals, although there were often missing images in the webarchive which were blamed on computer problems and interruptions in the microwave internetconnection at the radar. A more reliable radar file transfer routine will be investigated for the future.High speed Internet was installed for the pilots in Calgary and Red Deer so that the pilots could closely

monitor the storm evolution and motion. This gave the pilots better knowledge of the storm situationthey were going to encounter when they were launched.


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Figure 26: Jason Goehring in the communications control room, showing the CIDD, TITAN, andMeteo/Airlink computers.

Figure 27: TITAN dual-display showing the various radar pictures and satellite photo available to the radar

controller on 28-July-2005.

A new Configurable Interactive Data Display (CIDD) computer system was installed last year. The newCIDD system was routinely set to display an animated 1-hour movie loop of the higher resolution polarradar data, super-imposed on a terrain map background. An example of the WMI-NCAR CIDD(Configurable Interactive Data Display) system used this year is shown in Figure 28.


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Alberta Hail Suppression Project 2005 Field Program Final Report Page:

Documents

Wmi Alhap Final Report 2005