Danger in a flash Published July 30, 2010 By Emily Wolfgeher 72nd Air Base Wing Safety Office TINKER AIR FORCE BASE, Okla. -- Flash floods are the No. 1 weather-related killer in the United States. These floods occur within a few minutes or can build up over hours of excessive rainfall. Previous heavy rainfall can saturate the ground, making flooding more likely with lower levels of rainfall. Flash floods can roll boulders, tear out trees, destroy buildings and bridges, and scour out new channels. Rapidly rising water can reach heights of 30 feet or more. There will not always be a warning that these deadly, sudden floods are coming. Most flash flooding is the result of slow-moving thunderstorms, thunderstorms repeatedly moving over the same area or heavy rains from hurricanes and tropical storms. With some safety planning the risks associated with these weather events can be reduced. Plan ahead Identify where to go if told to evacuate. Choose several places...a friend's home or a motel in another town, or a shelter. Get to higher ground Even 6 inches of fast-moving flood water can knock you off your feet, and a depth of 2 feet will float most cars. Never try to walk, swim, or drive through such swift water. If you come upon flood waters, stop, turn around and go another way. How can a foot or two of water cost you your life? Water weighs 62.4 lbs. per cubic foot and typically flows downstream at 6 to 12 miles an hour. When a vehicle stalls in the water, the water's momentum is transferred to the car. For each foot the water rises, 500 lbs. of lateral force are applied to the car. The biggest factor is buoyancy. For each foot the water rises up the side of the car, the car displaces 1,500 lbs. of water. In effect, the car weighs 1,500 lbs. less for each foot the water rises. That is how two feet of water can carry away most automobiles. Listen to warnings When a flash flood warning is issued for your area, or the moment you realize that a flash flood is imminent, act quickly to save yourself. You may have only seconds · Get out of areas subject to flooding. This includes dips, low spots, canyons, washes, etc. · Avoid already flooded and high velocity flow areas. If you come upon a flowing stream where water is above your ankles, stop, turn around and go another way. · If driving, be aware that the road bed may not be intact under flood waters. Turn around and go another way. Never drive through flooded roadways. · If the vehicle stalls, leave it immediately and seek higher ground. Rapidly rising water may engulf the vehicle and its occupants and sweep them away. Remember, it's better to be wet than dead. · Be especially cautious at night when it is harder to recognize flood dangers. · Do not camp or park your vehicle along streams and washes, particularly during threatening conditions. · Children should never play around high water, storm drains or viaducts.