1. Communicating Societal Impacts --- An Objective Methodology WDTB Winter Weather Workshop October 9, 2002

2. Do Similar Storms Produce Different Impacts on the Public? Can We Develop a Set of Criteria so the Forecasters Can Objectively Evaluate Potential Impacts? How Can We Communicate the Potential Impacts to the Public? Do Similar Storms Produce Different Impacts on the Public? Can We Develop a Set of Criteria so the Forecasters Can Objectively Evaluate Potential Impacts? How Can We Communicate the Potential Impacts to the Public? The Challenge

3. Winter Storm Event “C”

5. Buffalo’s Greatest 24-hour Snowfalls Dec 9-10, 199537.9 inches Jan 10-11, 198225.3 inches Nov 20, 200024.9 inches Dec 15-16, 194524.3 inches Nov 30/Dec 1, ‘7920.1 inches Dec 9-10, 199537.9 inches Jan 10-11, 198225.3 inches Nov 20, 200024.9 inches Dec 15-16, 194524.3 inches Nov 30/Dec 1, ‘7920.1 inches

6. NYZ010-011-201635- ERIE-GENESEE- INCLUDING THE CITIES OF...BATAVIA...BUFFALO 435 AM EST MON NOV 20 2000...LAKE EFFECT SNOW WARNING THIS AFTERNOON AND TONIGHT....TODAY...SNOW DEVELOPING THIS MORNING...THEN A BAND OF HEAVIER LAKE EFFECT SNOW WILL MOVE SOUTH INTO THE AREA LATER THIS AFTERNOON. ACCUMULATION OF 2 TO 4 INCHES LIKELY BY RUSH HOUR ACROSS NORTHERN ERIE AND GENESEE COUNTIES. HIGH ABOUT 35. SOUTH WINDS 10 TO 15 MPH BECOMING SOUTHWEST 15 TO 25 MPH..TONIGHT...BLUSTERY WITH LAKE EFFECT SNOW PRODUCING TOTAL ACCUMULATION OF 6 TO 8 INCHES BEFORE MOVING SOUTH OF THE REGION BY MORNING. LOW IN THE MID 20S. SOUTHWEST WINDS 20 TO 30 MPH CAUSING BLOWING AND DRIFTING SNOW. CHANCE OF SNOW 100 PERCENT..TUESDAY...CONTINUED BLUSTERY WITH SNOW LIKELY. HIGH NEAR 30. CHANCE OF SNOW 80 PERCENT. Monday 4AM Forecast

7. Effects of Chestnut Storm Buffalo Airport Closed 24 Hours All Roads Closed… Including NY Thruway Thousands stranded.. Including over 2500 school children Power Outages Affecting 10,000 Buffalo Airport Closed 24 Hours All Roads Closed… Including NY Thruway Thousands stranded.. Including over 2500 school children Power Outages Affecting 10,000 Activation of 200 National Guard Gov Pataki Declares State of Emergency $43.5 Million in Overall Damage in West NY ($20M Erie Co) Postponement of Sabres/Flyers Games

8. Are All Major Lake Effect Storms Alike? “Gary” Dec 10, 1995 “Chestnut” Nov 20, 2000

9. Similarities Between Gary and Chestnut States of Emergency Declared Buffalo International Airport Closed Down New York State Thruway Closed Buffalo Sabres Games Postponed States of Emergency Declared Buffalo International Airport Closed Down New York State Thruway Closed Buffalo Sabres Games Postponed

10. There’s More to a Warning Than The Amount Total Snowfall Clean up Costs (in $ Millions)

11. There’s More to a Warning Than The Amount Total Snowfall Days of Cleanup

12. There’s More to a Warning Than The Amount Total Snowfall Number Stranded Schoolchildren

13. Timing of this storm was CRITICAL !!! Gary Occurred During a WEEKEND Chestnut Occurred on the FIRST DAY of the WORKWEEK at Rush Hour.

14. Chestnut Struck With Perfect Timing Rush hour Hourly Snowfall

15. Major Winter Storms Have to be Handled Individually One 24” Snowstorm May Be Totally Different From Another 24” event Must be Able to Highlight IMPACT POTENTIAL The Forecaster Must Assess Societal Impacts One 24” Snowstorm May Be Totally Different From Another 24” event Must be Able to Highlight IMPACT POTENTIAL The Forecaster Must Assess Societal Impacts

16. Assessing Societal Impacts An Objective Approach Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions

17. Assessing Societal Impacts Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions

18. Time of Day / Day of Week Weekend 7 AM to 4 PM: Some activity, church, shopping, events (2) 4 AM to 7 AM: Very little activity (1) Weekday 9 PM to 5 AM: Little activity, removal crews good progress (1) 5 AM to 7 AM: Decisions made by officials, increased traffic (4) 7 AM to 9 AM: Rush hour (5) 9 AM to Noon: Reduced Activity. School dismissal decisions? (3) Noon to 4 PM: Work / School Dismissal Decisions (4) 4 PM to 6 PM: Evening Rush Hour (5) 6 PM to 9 PM; Evening activities, sports, restaurants, etc (2 to 4) Monday Prior To 5 PM (3)

19. Communicating Societal Impacts Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions

20. “Seasonality” First major snow of the season: (5) First storm after a long thaw: (4) Mid season storm during a period of sub freezing weather and daily light snows: (2) Late season, fast melting, warm ground: (2 or 3) First major snow of the season: (5) First storm after a long thaw: (4) Mid season storm during a period of sub freezing weather and daily light snows: (2) Late season, fast melting, warm ground: (2 or 3)

21. Communicating Societal Impacts Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions

22. Type of Snow Wet: (3 to 5) difficult in driving and removing; but easier to treat chemically due to temps; roof collapses; “heart attack snow” Fluffy; (1 to 3) ease in removal; more difficult to treat; greasy driving Windy: (3,4) drifting & visibility problems, (especially with dry fluffy snow) Wet: (3 to 5) difficult in driving and removing; but easier to treat chemically due to temps; roof collapses; “heart attack snow” Fluffy; (1 to 3) ease in removal; more difficult to treat; greasy driving Windy: (3,4) drifting & visibility problems, (especially with dry fluffy snow)

23. Communicating Societal Impacts Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions Timing of the Storm (Day of Week / Time of day) “Seasonality” Type of Snow Post Storm Conditions

24. Sub freezing, wintry: Snow to hang around and pile up (4-5 early-mid winter, 3 late) Mild, above freezing long term: Snow will melt off or diminish in a few days (2) Mild, short term: Snow to change to rain (1 or 2) but (3-4 if changing to IP/ZR) Sub freezing, wintry: Snow to hang around and pile up (4-5 early-mid winter, 3 late) Mild, above freezing long term: Snow will melt off or diminish in a few days (2) Mild, short term: Snow to change to rain (1 or 2) but (3-4 if changing to IP/ZR)

25. Actual Warning - “Generic” Urgent - Winter Weather Message National Weather Service Buffalo NY 445 AM EST Mon Nov 20 2000...Plowable Snowfall Expected for Parts of Western New York Today....A Compact Low Pressure System near Lake Huron this Morning Will Track Just to the North of the Region Tonight and Tuesday and this Will Result in a Widespread Snowfall with Bands of Lake Effect Snow Developing Downwind of Lakes Erie and Ontario. As the Storm System Approaches the Region this Morning a General Snowfall Will Develop over the Far Western Counties. The Snowfall Will Become Lake Enhanced over Parts of the Niagara Frontier by Midday While Light Snow Will Spread Across the Finger Lakes and over Sites East of Lake Ontario. Most Areas Will Receive a Couple Inches of Snow by Nightfall...With as Much as 6 Inches of Snow Possible over Parts of the Niagara Frontier. Tonight...

26. URGENT ‑ WINTER WEATHER MESSAGE NATIONAL WEATHER SERVICE BUFFALO NY 445 AM EST MON NOV 20 2000...Plowable Snowfall Expected for Parts of Western New York Today....A Compact Low Pressure System near Lake Huron this Morning Will Track Just to the North of the Region Tonight and Tuesday and this Will Result in a Widespread Snowfall with Bands of Lake Effect Snow Developing Downwind of Lakes Erie and Ontario. As the Storm System Approaches the Region this Morning...a General Snowfall Will Develop over the Far Western Counties. The snowfall will Become Lake Enhanced over Parts of the Niagara Frontier by Midday While Light Snow Will Spread Across the Finger Lakes and over Sites East of Lake Ontario. By mid afternoon a band of heavy lake effect snow will develop over the northern suburbs of Buffalo. This band of heavy snow will shift south through the metropolitan area later this afternoon and evening...which will greatly impact this evenings rush hour. Value Added Information

27. NYZ010 ‑ 011 ‑ 201623 ‑ ERIE NY ‑ GENESEE NY ‑ INCLUDING THE CITIES OF...BUFFALO NY...BATAVIA NY...Lake Effect Snow Warning For This Afternoon And Tonight... A General Snowfall Will Develop This Morning And Produce Accumulations of 2 to 3 Inches By Nightfall. This Snowfall Will Be Accompanied by a Band of Heavier Lake Effect Snow That Will Develop to The North of Buffalo Early This The Afternoon. This Band of Heavy Lake Effect Snow Is Expected to Slowly Drift to The South Across Genesee And North Central Erie County Later This Afternoon And Evening...Where Accumulations of up to 6 Inches Are Possible by Nightfall. The Steadiest And Heaviest Snow For The Buffalo Metropolitan Area Is Expected to Fall Between 2 and 6 PM. Commuters During This Evenings Rush Hour Will Likely Experience Very Difficult Driving Conditions. Snowfall Rates of an Inch or Two an Hour, Combined with a Heavy Volume of Traffic, Could Clog Many of the Major Arteries Around The Metropolitan Area. Motorists Should Be Prepared For a Slow and Difficult Evening Commute.

28. Addressing Societal Impacts If any of the impact criteria are ranked at a category 4 or 5 by the consensus forecast… –Then include a specific impact statement within the watch/warning. –Will allow officials to delineate between typical and high-impact storms. If any of the impact criteria are ranked at a category 4 or 5 by the consensus forecast… –Then include a specific impact statement within the watch/warning. –Will allow officials to delineate between typical and high-impact storms.

29. Communicating Societal Impacts Alerts Planning Officials To Critical Situations Give School/Town Officials Time to Plan Highlight Storms That Could Produce Emergency Situations From Those That Won’t Alerts Planning Officials To Critical Situations Give School/Town Officials Time to Plan Highlight Storms That Could Produce Emergency Situations From Those That Won’t