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Sociological Factors Impacting Beach Attendance. Applications to Beach Hazards Risk Communication. Megan Dodson Beach Hazards Program Manager National Weather Service Marquette, MI. How does the NWS inform the Public About The Various Beach Hazards?. - PowerPoint PPT Presentation
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Sociological Factors Impacting Beach Attendance
Applications to Beach Hazards Risk Communication
Megan DodsonBeach Hazards Program Manager
National Weather Service Marquette, MI
How does the NWS inform the Public About The Various Beach Hazards?
NWS Risk Communication: Recreational Beach Forecasts (SRF)
Issued Daily from Memorial Day through Mid September
Swim Risk: Denotes the Risk of Strong Currents and Waves
Low, Moderate, High Risk
Swim Risk Outlook [Optional]
NWS Risk Communication: Beach Hazards Statements
A supplement to the Rec. Beach Forecast
Heighten Awareness on Critical Beach Days [appears on the WWA map]
Provide Additional Decision Support To Beach Managers on Critical Beach Days
What Constitutes a Critical Beach Day?
High Swim Risk + Increased Beach Attendance
High likelihood of a drowning/rescue incident occurring
What Conditions Increase Beach Attendance?
Sociological Factors Impacting Beach Attendance
433 Current Related Rescues/Fatalities Air T, Water T, Cloud Cover,
Precipitation, Day of the Week, Holiday Incidents by Lake
Beach Attendance over 97 days
Air T, Cloud Cover, Precipitation, Day of the Week, Holiday
Great Lakes Current Incident Database McCarty’s Cove Study: Lake SuperiorMarquette, MI
Holland State Park Seasonal Beach Attendance vs. SW Lower MI Seasonal
Climate Summary Beach Attendance (4 Years) Avg. seasonal Max T Avg. Lake MI Water T
Great Lakes Current Incident Database
5%
48%
47%
Cloud Cover During Incidents2002-2013
CloudyPartly-Mostly CldyMostly Clear
<55 55 to 60
61 to 65
66 to 70
71 to 80
>80 Missing0
50100150200250
015 46
98
239
25 10
Air Temperatures Observed Dur-ing Current Related Incidents
2002-2013
Air Temperature (F)
Num
ber o
f Inc
iden
ts
<5050-60
61-6566-70
71 to 75
76 to 80
>80
Missing
050
100150200250
1 24 34
98
210
364
26
Water Temperatures Observed During Current Related Incidents
2002-2013
Water Temperature (F)
Num
ber o
f Inc
iden
ts
Precipitation:
Only 4.2% of incidents occurred while it was raining!
Swim Season on the Great Lakes
MayJune
Early Ju
ly
Late Ju
ly
AugustSept
October
0
50
100
150
200
250
0
10
20
30
40
50
60
70
80
90
Current Related Incidents 2002-2013 vsNormal Avg. Air Temperature and Average Lake Michigan
Water Temperature
GLCID
Holland, MI Air T
Lake MI Water T
Num
ber o
f Inc
iden
tsA
ir/Water T
emperature (F)
Great Lakes Current Incident DatabaseCloudy, Rainy Days
18%
58%
14%5% 5%
Temperatures During In-cidents on Cloudy Days
≥7065-6960-6455-59M
Water Temperatures on Cool, Cloudy Days
Air T: 60-64⁰ F…….Water T: 70 to 75⁰F
Air T: 55-59⁰F……Water T: 60⁰F (only 1 incident)
85% Air T≥65⁰F
Generally Short & Light
Showery vs Steady
[2-5 hr period]
61%T-Storms
McCarty’s Cove: Beach Attendance Study on
Lake Superior Marquette, MI
<55 55-59 60-64 65-69 70-74 75-79 80-1000
50100150200250300350400450
17 27 55
136171
233
440
Average Beach Attendance By Air Temperatures (F)
Max Temperature (F)
Aver
age
Beac
h Att
enda
nce
Increased beach attendance with warmer temperatures
Decrease in beach attendance with cloudy skies
Partly-Mostly cloudy average includes the two days with highest beach attendance: 1500 (July 4th), 2000 (NMU Welcome Picnic Campus Cru, Aug 25).
Cloudy Pt-Mo Cldy Sunny0
100
200
300
400
500
600
120
598528
Average Beach Attendance By Cloud Cover
Cloud Cover
Aver
age
Beac
h Att
enda
nce
McCarty’s Cove: Beach Attendance Study onLake Superior in Marquette, MI
CLOUDY RAIN
CLOUDY DRY PT-MO CLDY RAIN
PT-MO CLDY DRY
SUNNY DRY0
100
200
300
400
500
600
31 410 20
9150 70 50
119
330
150
314375
583 600
Average Beach Attendance ByCloud Cover & Precipitation
T<=60T 61-65T>=66
Clouds and Precipitation
Aver
age
Beac
h Att
enda
nce
Rain:
*Includes Steady and Showery Precipitation
*Average Beach Attendance With Steady Rain Only: 31
*Beach Attendance does not mean visitors were swimming!
Southwestern Lower Michigan:Yearly State Park Beach Attendance
Year Number of Day Use Visitors
Average Maximum
Temp. Departure
from Normal
Maximum Lake MI Temp.
During Peak Swim
Season
Minimum Lake MI Temp.
During Peak Swim
Season
2009 3,817,076 -2.5 20 18
2010 4,271,118 3.43 24 22
2011 4,315,294 1.6 23 21
2012 4,740,222 4.7 23 21
2013 3,868,097 -0.2 21 18
State Parks Used: Grand Haven, Ludington, Muskegon, and Holland State Parks
SW LOWER MI STATS (GRR):
2009: 5th Coldest Summer on Record (1985-2009)
2012: 10th Hottest summer on record
(1985-2012)
2013: Coldest summer since 2009, wildest temperature swings occurred during the peak swim season
Weather Conditions Summary
Air & Water Temperatures ≥ 65 F
Sunny to Partly-Mostly Cloudy [Temperature Dependent]
Dry or Isolated showers/T-storms [Temperature Dependent]
Favorable Beach Days would be Characterized by:
How Does Beach Attendance Vary on Holidays and Weekends? What About Time of Day?
Additional Sociological Factors: Time Of Day
00:00-5:29
5:30-9:59 10:00-11:59
12:00-14:59
15:00-17:59
1800-20:59
21:00-21:59
22:00-23:59
0
20
40
60
80
100
120
140
160
180
0 3 6
121
171
77
8 2
Time of Current Related Incidents2002-2013
Time (LDT)
Num
ber o
f Inc
iden
ts
Diurnal Temp Trend
MAX T
Additional Sociological Factors: Day of the Week
Thursday
Friday
Saturd
ay
Sunday
Monday
Tuesday
Wednesd
ay0
5
10
15
20
25
30
Day of The Week For Beach Attendence or Current Related Incidents
GLCID (2002-2013)
McCartys Cove (2013) Lake Superior
U.S Gensini & Ashley (2009)Pe
rcen
tage
Additional Sociological Factors: Holidays & Weekends
More than 50% of rip current rescues in east-central Florida occurred on major holidays and weekends due to increased tourism (Lascody, 1998)
In a studies on rip current fatalities across the U.S., most occurred on weekends (Gensini & Ashley, 2009; Paxton, 2011)
In the McCarty’s Cove Study on Lake Superior, Beach attendance spiked from an average of ~250 visitors/day to 1500 visitors on the 4th of July (A Thursday).
Weather: Sunny to Partly Cloudy, Max T: 81ºF
In the GLCID, only 5% of victims drowned on the 4th of July Holiday (2nd-6th).Only 3% occurred on Labor Day and Memorial Day combined.
Weather and Lake condition dependent
Generalized Conclusions About Beach Attendance
Beach Attendance increases on Holidays and Weekends, especially Sunday
People don’t swim at night or early in the morning (midnight to 6 am LDT).
People don’t swim when the air temperature is <55ºF.
People don’t swim on cloudy rainy days unless:*Precipitation is short lived, showery [less than 2-3 hrs].*Temperature is ≥65ºF .*Warmer water temps (Majority Tw >65ºF).
Operational ApplicationsBeach Hazards Statements:
Heightening public awareness on days we expect a large number of incidents
High waves/dangerous currents + high beach attendance
Use the sociological factors to lighten operational workload/limit unnecessary issuance of statements:
Less swimmers = less risk of an incident (all other things equal)
Let the Recreational Beach Forecast speak for itself
No hard & fast rules, use forecaster discretion
High Swim Risk
Max T<55ºF Max T 55ºF-64ºF Max T≥ 65ºF
No BH.S Water T< 50FYes
No
Issue BH.S
Which Weather Describes Today Best?
Steady/Frequent Rain & Clouds Sunny/Partly to Mostly CloudyDry or intermittent Rain/T-Storms
Issue BH.SHoliday?
Issue BH.SNo BH.S
YesNo
NWS MQTStatement Guidance
References• Dodson, M., 2013: Studies on Beach Attendance: McCarty’s Cove, Lake
Superior and Southwest Lower Michigan. Local Study at NWS Marquette, Michigan. Contact NWS Marquette for questions.
• Dodson, M., Guenther, D.,2013: Great Lakes Current Incident Database. Local Study at NWS Marquette, Michigan. Contact NWS Marquette for any questions.• Evanoff, M., 2013. Beach Attendance Statistics from Michigan State
Parks. Personal Correspondence.• Lascody, R.L., 1998: East Central Florida Rip Current Program. National
Weather Digest, 22(2), 25-30.• National Weather Service: Grand Rapids, Northern Indiana, Marquette,
2009-2013. Beach Hazards Statements, Rec. Beach Forecasts, and Climate Summaries.
• Paxton, C., 2011: Meteorological Data Analysis of Rip Current Drowning. Rip Currents: Beach Safety, Physical Oceanography, and Wave Modeling, S. Leatherman and J. Fletemeyer, Eds., CRC Press, 161-174.
