Rapid City was inundated by a terrible flood June 9-10, 1972, when approximately 12-15 inches of rain fell in just five to six hours over the Rapid Creek watershed.  This steep mountainous terrain was not able to absorb this tremendous amount of water and a flash flood resulted.  After a wall of water rushed down the creek towards Rapid City, causing the dam of Canyon Lake on the western edge of the city to burst, a gigantic wall of water rushed through the town killing 238 people in just a few hours.  The picture below is a part of the historic documentation of the flood.  This particular picture shows a pile of cars that was formed by flood waters near downtown Rapid City. (Publication of the National Oceanic and Atmospheric Administration Central Library.)  For additional information about this disastrous event, visit the Rapid City National Weather Service site.