National Weather Service United States Department of Commerce

Severe Thunderstorms and Heavy Rainfall in the Southern Plains; Heat Continues in the West

Strong to severe thunderstorms may bring areas of excessive rainfall and flooding over parts of the southern Plains today through Friday. Hot to dangerously hot temperatures are forecast across portions of the Pacific Northwest and southern Great Basin today. Gusty winds, dry, and hot conditions will bring critical fire weather to parts of central Washington state today. 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.