Most communities in the United States can experience some kind of flooding after spring rains, heavy thunderstorms or winter snow thaws.
Floods can be very slow or fast rising, but generally develop over a period of days.
Dam failures are potentially the most catastrophic of flood events. A dam failure is usually the result of structural damage caused by a major event such as an earthquake. When a dam fails, a large amount of water is suddenly let loose downstream, destroying anything in its path. Flash floods are usually the result of intense storms dropping large amounts of rain within a brief period of time. Flash floods occur with little or no warning and can reach full peak in only a few minutes.