On May 31, 1889, an 11-inch rain following an already wet spring led to the catastrophic failure of the South Fork Dam located 14 miles up a narrow canyon from Johnstown, Pa. The water over topped ...

Heavy rains brought the South Fork dam above the city of Johnstown to the brink of collapse. When the structure finally gave in, a 12-meter high (40 ft) wall of water rushed down from the mountain.

The flood was caused when the South Fork Dam failed due to torrential rainfall, causing around three billion gallons of water to flow in Johnstown's direction. Buildings were crushed, nearly 100 ...