Flash flooding is rapid flooding of low-lying areas,
rivers and
creeks that is caused by the intense rainfall associated with a
thunderstorm. Flash flooding occurs when the ground under a storm becomes saturated with
water so quickly that it cannot be absorbed. The runoff collects in low lying areas and flows rapidly downhill. As a result, anything in its path is suddenly in rising water. These most often occur in dry areas that have recently received
precipitation, but the flash flood can flow for a long distance as long as there is a path downhill.