Floods - Under Construction
Floods and flash floods occur all around the world. Communities particularly at risk are those located in low-lying areas, near water, or downstream from a dam.
- Floods are the most common and widespread of all natural disasters except for fire. Most communities in the United States can experience some kind of flooding after spring rains, heavy thunderstorms, or winter snow thaws. Floods can be slow, or fast rising but generally develop over a period of days.
- Flash floods usually result from intense storms dropping large amounts of rain within a brief period. Flash floods occur with little or no warning and can reach full peak in only a few minutes. Dam failures are potentially the worst flood events. A dam failure is usually the result of neglect, poor design, or structural damage caused by a major event such as an earthquake. When a dam fails, a gigantic quantity of water is suddenly let loose downstream, destroying anything in its path.
During the last century, significant floods in the United States have caused more than 10,000 the deaths with property cost over $1 billion each year.
Some examples of flash floods: On June 9, 1972, Rapid Creek in South Dakata overflowed its banks after the storm dumped over 15 inches of rain in 5 hours. 238 people perished; and there was $164M in damages. On July 31, 1976, the Big Thompson River near Denver overflowed after an extremely heavy storm. A wall of water 19 feet high roared down the Big Thompson Canyon where many people were camping. 140 people perished and millions of dollars of property were lost.