1. “Cost” of Time Spent during Tornado Warnings 2000 - 2004 Somer Erickson Meteorology/Economics NSSL/OU Boulder Summer WAS*IS July 2006

2. Why Tornado Warnings? Highly visible product Want as few warnings as possible to protect lives and property Different way of looking at false alarm problem → 50% of tornadoes warned for from 1986 -2004, but 66% warned for during 2000 – 2004.

3. Value vs. Cost Value –Fatality/injury reduction (perhaps 400 lives saved per year for the warning system) Cost –Cost of warning system –Cost to the public of time taking precautions $15 per hour (typical value)

4. What I have done Looked at every tornado event reported and tornado warning issued by National Weather Service (1986 – 2004) –Population in the warned county –Area of the warned county –Length of time of the warning

5. Mean Warning Time 2000 –.65 hours 2001 –.65 hours 2002 –.65 hours 2003 –.69 hours 2004 –.69 hours 5 year average: ~.67 hours

6. Number of Warnings 2000 → 2906 2001 → 2903 2002 → 2812 2003 → 4023 2004 → 4691 TOTAL = 17,335 (5 years) AVERAGE = 3,467

7. Total Warn Time 2000: 1902.2 hours 2001: 1876.7 2002: 1822.9 2003: 2763.3 2004: 3237.8 Average: 2320.6 hours

8. Person Hours (time x population) 2000: 195.2 million (67,166/warning) 2001: 187.9 (64,727) 2002: 185.5 (65,976) 2003: 292.7 (72,570) 2004: 360.2 (76,783) MEAN = 244.3 (70,464)

9. COST ($15/person hour)

10. Other Results...

11. Most Warnings (2000 – 2004) 1.Texas – Harris County (63 warnings) 2.Colorado – Washington County (48) 3.Colorado – Lincoln County (43) 4.Texas – Liberty County (41) 5.Lousiana – St. Tammany Parish (39) 1138. Oklahoma – Cleveland County (6) → Colorado – Boulder County (0)

12. Most Warned Counties (2000-2004) 1. Texas – Harris County (8.3 hours/year) 2. Colorado – Washington County (6.5) 3. Colorado – Lincoln County (5.9) 4. Texas – Liberty County (5.7) 5. Missouri – Wayne County (5.6) 1129. Oklahoma – Cleveland (0.8)

13. Population Time (2000 – 2004) 1.Texas – Harris County 2.Florida – Miami-Dade County 3.Illinois – Cook County 4.Florida – Palm Beach County 5.Florida – Broward County 216. Oklahoma – Cleveland County

14. Harris County 3rd most populous county in United States $450 million a year ( ~ 13% of national total) 68 warnings –14 per year –22 verified –68% were false alarms 30 Tornadoes – 6 per year –1 F3 –2 F2

15. Polygon Warnings Potentially: Decrease warning area size ↓ Decrease costs

16. Future Would like to continue this work for my PhD but…. …..there is no ECONOMICS (aka funding) to do so! Any help would be greatly appreciated!?!

17. Questions? tornadosomer@ou.edu