Severe Weather and Heavy Rain from the Great Lakes to the Mid-Atlantic; Heat Persists in the East

Widespread strong thunderstorms with damaging winds and locally heavy rain are expected from the Upper Ohio Valley into the southern Mid-Atlantic today and portions of the central Appalachians and Carolinas on Saturday. Monsoonal moisture will bring a flash flooding threat to the Desert Southwest. Sweltering heat persists from the Plains to the southern Mid-Atlantic through tonight. Read More >

Definitions of Flood and Flash Flood

Flood: An overflow of water onto normally dry land. The inundation of a normally dry area caused by rising water in an existing waterway, such as a river, stream, or drainage ditch. Ponding of water at or near the point where the rain fell. Flooding is a longer term event than flash flooding: it may last days or weeks.

Flash flood: A flood caused by heavy or excessive rainfall in a short period of time, generally less than 6 hours. Flash floods are usually characterized by raging torrents after heavy rains that rip through river beds, urban streets, or mountain canyons sweeping everything before them. They can occur within minutes or a few hours of excessive rainfall. They can also occur even if no rain has fallen, for instance after a levee or dam has failed, or after a sudden release of water by a debris or ice jam.

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