What is a flash flood and what causes it?

Question

What is a flash flood and what causes it?

Answer 1

A flash flood is a rapid flooding of low-lying areas caused by the intense rainfall associated with a thunderstorm, or multiple thunderstorms. It occurs when the ground becomes saturated with water that has fallen too quickly to be absorbed. The runoff collects in low-lying areas and rapidly flows downhill.

Answer 2

Sudden,brief and fast-moving surges of water in sheets or along normally dry channels are typical of desert or semi-arid areas following intense,but short duration,rainfall.These are called flash floods.Flash floods can reach their maximum flow in minutes and achieve heights of even 3 meters.Sudden torrential rain concentrated in a narrow channel can produce a flash flood.