Flash flood

Rapid flooding of low-lying areas

A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes, and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, or tropical storm, or by meltwater from ice and snow. Flash floods may also occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889.

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