75 percent of US deaths from hurricanes are from water, not wind
By: JON ERDMAN
Hurricanes are rated by wind, but you should fear the water more.
According to the National Hurricane Center, storm surge and rainfall flooding combined for 75 percent of all deaths in the U.S. from hurricanes, tropical storms or tropical depressions from 1963 to 2012.
Deaths from a tropical cyclone's winds or embedded tornadoes accounted for only 10 to 15 percent of fatalities in the U.S. in that time.
This may sound counterintuitive, since Category 1, 2, 3 hurricanes are rated based on their maximum sustained winds.
Certainly a hurricane or even a strong tropical storm is capable of wind damage.
Despite that devastation, 26 deaths – 15 in South Florida – were directly attributed to the hurricane.
Storm Surge: The Deadliest Threat
Half of all U.S. deaths from tropical cyclones are due to the storm surge, the rise in water levels from the tropical cyclone's winds piling water toward the coast just before and during landfall.
Storm surge is not simply a function of the maximum winds.
Hurricane Ike was not a "major" (Category 3 or stronger) hurricane at landfall in Galveston, Texas in September 2008. Yet the size of Ike's wind field generated a 15-20 foot storm surge that wiped out most structures on the Bolivar Peninsula of Texas.
Well before the modern age of satellites, television, and instant communication, a storm surge of up to 15 feet, with battering waves, claimed most of the 8,000 to 12,000 lives lost in the Galveston, Texas 1900 hurricane, the nation's deadliest.
To more clearly communicate the threat from storm surge, the National Hurricane Center will prepare experimental storm surge inundation maps when a hurricane or tropical storm is near landfall.
These maps will identify how deep the storm surge inundation may be above ground level in a worst-case scenario based on the forecast track, intensity and wind field.
Before a hurricane threatens, find out if you live in an evacuation zone. Knowing this – and heeding evacuation orders from local emergency managers – could save your life and those of your family members.
Rainfall Flood Threat
Let's consider two examples to illustrate this threat.
There was surge flooding along the coast from the Outer Banks of North Carolina to southern New England, but this storm wasn't just a coastal danger.
Irene's legacy was its epic inland rainfall flooding from parts of New York state into New England, particularly in Vermont, where almost 2,400 roads, 800 homes and businesses and 300 bridges were destroyed or damaged from the flooding.
Of the 41 total U.S. deaths attributed to Irene, 21 of those were from rainfall flooding.
Now consider a system that wasn't officially a depression anymore when it inflicted its havoc.
Tropical Storm Allison in June 2001 soaked the Houston metro area as it made landfall, then dropped a massive second delugewhen its remnants moved south back over the Texas coast a few days later. Up to 37 inches of rain swamped parts of America's fourth largest city.
This $9 billion tropical storm, the costliest tropical storm in U.S. history, claimed 41 lives in the U.S. Twenty-seven of those died from rainfall flooding.
Hurricane Agnes in 1972 was barely so at landfall, Category 1 at its Florida panhandle landfall. However, it's final move and subsequent stalling over the Northeast triggered massive flooding. Of the 122 U.S. deaths, 113 were due to rainfall flooding.
The bottom line here is to respect the power of water in tropical cyclones. Don't become a statistic.