Hurricanes have the potential to dump enormous amounts of rain, sometimes as much as 10-15 inches, on areas they pass over, and this rainfall can continue long after the storm moves inland.
In addition, as these storms strike the coast, they can push huge walls of water – the storm surge – into coastal areas, causing catastrophic damage, the kind witnessed in Mississippi and Louisiana during Hurricane Katrina in 2005.
Storm Surge
- Surges can range from four to six feet in minimal hurricanes to greater than 20 feet in stronger storms.
- A storm surge can sweep across the coastline near landfall in a swath 50 to 100 miles wide.
- In addition to the height of the surge itself, devastating waves can be present at the top of the surge.
- Damage is generally worst when the point of landfall occurs where offshore waters are shallow.
- Storm surge, not wind, is the greatest threat to life and property near the coast.
- Hurricane Camille generated a 25-foot storm surge in Mississippi in 1969.
- Hurricane Hugo generated a 20-foot storm surge in South Carolina in 1989.
Flooding
According to records during the past 30 years:
- 59% of U.S. tropical cyclone deaths occurred in freshwater floods.
- 63% of all tropical cyclone deaths occurred in inland counties.
- 78% of children killed by tropical cyclones drowned in freshwater floods.
- 23% of U.S. tropical cyclone deaths occur to people who drown in, or attempting to abandon, their cars.
- A person can be swept away by six inches of moving water.
- An automobile can be swept off the road in 12 inches of moving water.
- Rainfall is typically heavier with slower moving storms.
*Sources: http://www.nhc.noaa.gov/ssurge/index.shtml and http://www.nhc.noaa.gov/HAW2/english/inland_flood.shtml