The 1970s were the worst decade for flash floods in U.S. history. Devastating floods struck Buffalo Creek, WV in February 1972 (125 fatalities); Rapid City, SD on this date in 1972 (237 fatalities); Big Thompson Canyon, CO in July 1976 (145 fatalities); Johnstown, PA in July 1977 (76 fatalities); and Kansas City, MO in September 1977 (23 fatalities). Flash floods killed an
average of 182 people each year during the 70s. Improvements in forecasting and warning (especially Doppler radar) have been effective in reducing the death toll. No single flash flood has killed more than 100 people since 1980 and the 10 year average annual death toll dropped as low as 65 during the 2000-2009 time period. But the running ten year average has been slowly edging back up. For the period 2002-2011, the average has crept back up to 78. 2011 was the deadliest year for flash floods (113) since 1998 when 136 people were killed.