Pennsylvania History includes the 1889 Johnstown Flood which was caused by wanton neglect of an earthen dam , where heavy rain caused a collapse on May 31st, 1889.
Johnstown, a steel town of 30,000 people lost 2200 residents when a wall of water raced down the narrow valley at 40 mph.
It was July 20, 1977 when a second severe flood hit Johnstown killing 84 people. The dams in the Conemaugh Valley failed as before when heavy rains inundated the region. Nearly 12 inches of rain fell in 10 hours.