n June of 1972, winds pushed moist air westward up the flanks of the Black Hills, forming severe thunderstorms. The huge thunderstorms remained over the mountains, where they dumped as much as 15 inches of rain in one afternoon and evening. This downpour unleashed a flash flood down Rapid Creek that was ten times larger than any previously recorded flood on the creek. The swirling flood- waters breached the dam at Canyon Lake,