CONSEQUENCES OF EXTREME WINDS & SEVERE STORMS Extreme Wind Speeds in the U.S. Severe Wind Types Severe Wind Types Non-tornadic: All at Mount Washington, N.H. Mountain Lee Waves & Extratropical Cyclones Downbursts Highest Peak gust PNoted first by Fujita (1975) PVertical downward jet from a thunderstorm PFrequently mistaken for tornados PTypes: Speed (m/s) PMountain 103.6 5-min speed 24-hr speed Monthly speed 84.2 57.2 31.1 Annual speed 15.6 Lee Waves Chinook, Fohn Winds Ground speeds to 30 m/s (eg. Boulder) Gust factors from 2 to 7 PExtratropical Cyclones Weather storms rising outside L tropical lattitudes Typical storms and weather seen over most of USA Ground speeds to 40 m/s Microburst: Macroburst: 75 m/s 60 m/s 28T & F1 1 F1 3 7T & F1 Severe Wind Types Severe Wind Types Tornadoes Cyclones, Hurricanes or Typhoons WEAK TORNADO 10-7 to 10-3/yr PLength: 150-150,000 m PWidth: 15-1,200 m PSpeed Tangential: 25-150 m/s STRONG TORNADO PSpeed Vertical: < 80 m/s PSpeed Radial: < 50 m/s PProbability: P Large scale organized rotating flow system over sea surface P Created when sea surface temperature is > 26.5O C P Energized by latent heat release P Eye translates at 2 - 10 m/s P Wind speeds range from 33 to > 69 m/s Miami Daytona Savanah Beach 50 mi 6T & F1 4 5 5T & F1 Hurricane Andrew Hurricane Size 300 mi Hurricane Andrew Saffir/Simpson Damage Potential Scale Ranges Category Central Pressure [mb (in Hg)] Winds [mph] Surge [ft] Damage 1 2 > 980 (28.94) 965-979 (28.50-28.91) 74-95 96-110 4-5 6-8 Minimal Moderate 3 4 945-964 (27.91-28.47) 920-944 (27.17-27.88) 111-130 131-155 9-12 13-18 Extensive Extreme 5 < 920 (< 27.17) > 155 > 18 Saffir-Simpson Category 4 Hurricane Catastrophic 6 F1 8 7 1T & F1 Hurricane Mitch Direct Impacts of Hurricane Andrew Total Cost $30 Billion: Hurricane Mitch R.A. Pielke, Jr. (1997) >20,000 dead and > 20,000 missing Refugees cross flood waters Insured Property - $16.5 B P 2000 people killed in mudslide down side of volcano Orphan from mud slide on volcano, Nicaragua Defense Dept - $1.4 B Uninsured Property - $0.35 B Federal Relief - $6.5 B Red Cross - $0.07 B Flood - $0.1 B Aircraft - $0.02 B Environment - $2.12 B Agriculture - $1.52 B Infrastructure - $1.4 B Saffir-Simpson Category 5 Hurricane 10 9 Current Potential for Catastrophic Losses in the United States Losses assumed proportional to wealth, inflation and population then adjusted to 1995$ P Multibillion $ storms are norm not the exception P Over 71 years the normalized losses were $339B: Average year $4.8 B/year Maximum year $74 B/year 43% of time < $1 B/year 25% of time > $5 B/year 18% of time >$10 B/year P Thus US has 1:6 chance of experiencing a $10 B loss P No evidence for any climatic change 11 1T & F1 1T & F1 Conclusions from Normalized Data Approach Children flee over damaged bridge, Guatemala City Bob Sheets (former director National Hurricane Center), 1995 PIf Hurricane Andrew had tracked 20 miles further north “total property damage would have exceeded $100,000,000,000" PHurricanes like we had in the 40's and 50's today would cost: $68,000,000,000 in Maryland and Virginia $106,000,000,000 in south Florida $104,000,000,000 in New England 13 9T 14 5T Prepared by Robert N. Meroney, June 2000