Some Background info…
Red Flag program Highlights life threatening fire conditions to fire
fighters and other fire management officials Assuming dry fuels exist, program is based
primarily on surface winds and RH
Full Fire WX program became operational across NE and KS this week including a Red Flag Program
Some Background info…
• KS statewide fire management meeting held on 4/20/06 in Salina
Implemented RFW program Defined criteria for the program, West vs. East
• NE statewide fire management meeting held on 6/20/06 in Hastings
RFW climatology for NE was presented RFW program was implemented with thresholds
based on presented climatology
Purpose• Provide data to discussion about Red Flag
Warning criteria
• Provide useful information to NWS offices regarding staffing strategies
• Provide useful information to NWS forecasters about normal red flag start and stop times
Methodology • Hourly surface weather observations were obtained for
30 years (1976-2005) at the following KS sites: Goodland (GLD) Hill City (HLC) Garden City (GCK) Dodge City (DDC) Concordia (CNK) Salina (SLN) Wichita (ICT) Topeka (TOP) Chanute (CNU)
Methodology (continued)• Hourly surface weather observations were obtained for
30 years (1976-2005) at the following NE sites: Valentine (VTN) North Platte (LBF) McCook (MCK) Hastings (GID) Norfolk (OFK) Omaha (OMA)
Methodology (Continued)• Roughly 3.9 million observations were reviewed using
Excel and locally written code.
• The study examined possible wind and relative humidity thresholds for red flag warnings:– Criteria 1 (winds >=15 mph / RH <15%)– Criteria 2 (winds >=25 mph / RH <15%)– Criteria 3 (winds >=15 mph / RH <20%)– Criteria 4 (winds >= 25 mph / RH <20%)
• Fuel information is not included in the study.
Criteria 1 Criteria 2 Criteria 3 Criteria 4
Station
<15%
>15 mph
<15%
>25 mph
<20%
>15 mph
<20%
>25 mph
OMA 20 11 106 101
OFK 105 64 248 233
GID 94 53 265 209
LBF 201 111 775 374
MCK 289 160 751 433
VTN 329 91 990 423
Number of NE Events 1976-2005
Criteria 1 Criteria 2 Criteria 3 Criteria 4
Station
<15%
>15 mph
<15%
>25 mph
<20%
>15 mph
<20%
>25 mph
OMA 1 < 1 4 3
OFK 4 2 8 8
GID 3 2 9 7
LBF 7 4 26 12
MCK 10 5 25 14
VTN 11 3 33 14
Average Number of NE Events / Year
Number of KS Events 1976-2005
Station<15%
>25 mph Station<20%
>15 mph
GLD 372 CNK 177
HLC 185 SLN 221
GCK 303 ICT 237
DDC 273 TOP 132
CNU 79
Average Number of KS Events / Year
Station<15%
>25 mph Station<20%
>15 mph
GLD 12 CNK 6
HLC 6 SLN 7
GCK 10 ICT 8
DDC 9 TOP 4
CNU 3
RH <= 15%
Wind >= 25mph
STATION EVENTS PER
YEAR
GCK 10
DDC 9
DODGE CITY CWA YEARLY RED FLAG EVENTS DDC,GCK 1976-2005
0
5
10
15
20
25
30
35
YEAR
# R
ED
FL
AG
EV
EN
TS
DDC
GCK
When do these events begin?
Avg Start Time = 20:16Z (14:16 LST / 15:16 LDT)
Avg Event Length ~ 2.9 hours
DODGE CITY RED FLAG EVENTS BY START TIME1976-2005
2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
12
22
53
64 62
40
15
3
0
10
20
30
40
50
60
70
HOUR (UTC)
# R
ED
FL
AG
EV
EN
TS
LBF Start Times…
Avg Start Time = 20:33Z (14:33LST / 15:33 LDT)
Avg Event Length ~ 2.3 hours
LBF RED FLAG EVENTS BY START TIME1976-2005
0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1
6
18
38
25
10 10
2
0
5
10
15
20
25
30
35
40
HOUR (UTC)
# R
ED
FL
AG
EV
EN
TS
OFK Start Times…
Avg Start Time = 20:14Z (14:14LST / 15:14 LDT)
Avg Event Length ~ 2.7 hours
OFK RED FLAG EVENTS BY START TIME1976-2005
0 0 0 1 0 0 0 0 1 1 0 0 0 0 2 4 6
23
40
61
4640
19
4
0
10
20
30
40
50
60
70
HOUR (UTC)
# R
ED
FL
AG
EV
EN
TS
ICT Start Times…
Avg Start Time = 20:01Z (14:01LST / 15:01 LDT)
Avg Event Length ~ 3.1 hours
WICHITA RED FLAG EVENTS BY START TIME1976-2005
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
69
23
5156
52
25
13
10
10
20
30
40
50
60
HOUR (UTC)
# R
ED
FL
AG
EV
EN
TS
Is there a “Red Flag Season” in the High Plains?
DODGE CITY RED FLAG EVENTS BY SEASON
JFM34%
AMJ36%
JAS10%
OND20%
JFM AMJ JAS OND
Some Conclusions…
• Red Flag events throughout the KS and NE domain typically start between 2000-2100UTC.
• There is no “well-defined” Red Flag season
• The preliminary thresholds that were established for KS agree with climatology and seem sufficient for Fire WX Operations.
Previous data along with the remaining KS and NE sites are available online at:
http://www.crh.noaa.gov/gld/?n=firewx/redflagclimo.php
Data Online…
Hopefully this data will act as a planning tool for fellow NWS personnel as well as Fire Management officials.