Natural Disaster. "Downstream flooding due to the partial or complete collapse of any impoundment. Dam failure is associated with intense rainfall and prolonged flood conditions. However, dam breaks may also occur during dry periods as a result of progressive erosion of an embankment caused by seepage leaks. Dam failure may also be caused by earthquake". (FEMA, Hazard Identification.... (CPG 1-34), 1985, p. A-3)