Flood and Flash Floods Main
Flash flood
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Driving through a flash-flooded road
Nepal Monsoon
A flash flood after a thunderstorm in the Gobi, Mongolia
A flash flood is a rapid flooding of geomorphic low-lying areas: washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields. Flash floods may 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. Flash floods are distinguished from a regular flood by a timescale of less than six hours.[1] The temporary availability of water is often utilized by foliage with rapid germination and short growth cycle, and by specially adapted animal life.
Contents
1 Causes 2 Hazards 3 Significant flash floods 4 See also 5 Further reading 6 References 7 External links
Causes
Flash floods can occur under several types of conditions. Flash flooding occurs when precipitation falls rapidly on saturated soil or dry soil that has poor absorption ability. The runoff collects in gullies and streams and, as they join to form larger volumes, often forms a fast flowing front of water and debris. Flash floods most often occur in normally dry areas that have recently received precipitation, but may be seen anywhere downstream from the source of the precipitation, even many miles from the source. In areas on or near volcanoes, flash floods have also occurred after eruptions, when glaciers have been melted by the intense heat. Flash floods are known to occur in the highest mountain ranges of the United States and are also common in the arid plains of southwestern United States. Flash flooding can also be caused by extensive rainfall released by hurricanes and other tropical storms, as well as the sudden thawing effect of ice
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Driving through a flash-flooded road
Nepal Monsoon
A flash flood after a thunderstorm in the Gobi, Mongolia
A flash flood is a rapid flooding of geomorphic low-lying areas: washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields. Flash floods may 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. Flash floods are distinguished from a regular flood by a timescale of less than six hours.[1] The temporary availability of water is often utilized by foliage with rapid germination and short growth cycle, and by specially adapted animal life.
Contents
1 Causes 2 Hazards 3 Significant flash floods 4 See also 5 Further reading 6 References 7 External links
Causes
Flash floods can occur under several types of conditions. Flash flooding occurs when precipitation falls rapidly on saturated soil or dry soil that has poor absorption ability. The runoff collects in gullies and streams and, as they join to form larger volumes, often forms a fast flowing front of water and debris. Flash floods most often occur in normally dry areas that have recently received precipitation, but may be seen anywhere downstream from the source of the precipitation, even many miles from the source. In areas on or near volcanoes, flash floods have also occurred after eruptions, when glaciers have been melted by the intense heat. Flash floods are known to occur in the highest mountain ranges of the United States and are also common in the arid plains of southwestern United States. Flash flooding can also be caused by extensive rainfall released by hurricanes and other tropical storms, as well as the sudden thawing effect of ice