1972 Black Hills flood

The Black Hills Flood of 1972, also known as the Rapid City Flood, was one of the most detrimental floods in the history of South Dakota. It took place on June 9–10, 1972^[2] in the Black Hills of Western South Dakota. 15 inches (380 mm) of extreme rainfall over six hours sent Rapid Creek and other waterways overflowing, flooding many residential and commercial properties in Rapid City. It also caused flooding of the Battle, Spring, Bear Butte, and Boxelder Creeks.^[3]

• http://en.wikipedia.org/wiki/1972 Black Hills flood