Widespread Precipitation and Gusty Winds in the West; Snow from the Great Lakes to the Northeast

A Pacific storm system is expected to bring strong winds and more precipitation to the western U.S., along with the likelihood of snowfall into the Sierra Nevada. Accumulating snow will develop downwind from the Great Lakes into parts of the Northeast through Saturday. Polar air will surge into the eastern half of the country this weekend. 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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