Black Hills Flood

The Black Hills Flood of 1972, in the Black Hills of Western South Dakota, USA, occurred on June 9, 1972. The extreme rainfall of around 15 inches (380 mm) of rain in 6 hours sent Rapid Creek and other creeks overflowing and flooded many residential and commercial properties around the Black Hills. During the night of June 9, the Canyon Lake Dam became clogged with debris and failed, resulting in 238 deaths and 3,057 injuries. Several bodies were never found. There were over 1,335 homes and 5,000 automobiles destroyed. The value of the damaged property was over $160M 1972 in dollars.

http://en.wikipedia.org/wiki/Black_Hills_flood