Areas of Severe Thunderstorms, Excessive Rainfall, and Extreme Heat Tuesday

In the Northern Plains into the Upper Great Lakes and Mid-Atlantic, heavy to excessive rain may bring flash and urban flooding Tuesday. Severe thunderstorms producing damaging winds are most likely over parts of the Dakotas into Minnesota Tuesday afternoon into the overnight, with other isolated storms producing hail or wind over the northern High Plains. Extreme heat returns to the southwest U.S. 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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