Natural Hazards. What are the greatest risks? Are these risks increasing? What are the costs associated with environmental hazards? Are the relative costs the same around the world? What controls these costs? How do we define risk?. So… What are common hazards.
Data is a 150 year average from 19th and 20th centuries (Keller, 1999).
Number of Hazard Events World WideType of Hazard No of Events
Tornadoes (U.S. only)
Wind (other than tornado)
Temperate winter storm
For 20th century data from WHO (2002), U.S. tornado data are only for 1950-1995 for only F2-F5 size events
Numbers of Deaths Associated with Natural Disasters Worldwide
Data for 20th century, based on WHO (2002) data.
Worldwide Hazard Ranking by CostType Cost
Cost of natural hazards, summarized by type for top 100 most costly events of 20th century (WHO, 2002).
F5 Tornado that hit Greensburg
Kansas, May 4, 2007
-Doppler radar gave a 20-minute warning
-Tornado was 1.5 miles across at its base
-95% of the town was leveled
Lightening strikes 100 times/second worldwide, with the greatest number of hits in central Africa. In the U.S. the greatest number of lightening strikes occur in Florida.
The Empire State building is hit on average 100 times/year.
Sean & Michael McQuilken, 1975