General view of debris following the Johntown Flood
On May 31, 1889 a torrential downpour brought an estimated ten inches of rain overnight into the Conemaugh River valley. Elias Unger, the president of the Club, living above the dam, saw by morning light that the lake was on the verge of cresting the dam. He marshaled as many men as he could to pile mud and rocks on top of the dam, and to unclog the spillway. Engineer John Parke rode to the nearest town, South Fork, to telegraph Johnstown that the dam was not holding. The word never made it to the general population. Some people were already trapped in their homes from the rising waters, and awaited rescue. At about three in the afternoon the dam breached, and millions of tons of water and collected debris came roaring down the valley.
Post-flood view of Main Street in Johntown
The people of South Fork fled up the hills and only four perished. The town of Mineral Point was utterly destroyed, killing sixteen. As the flood descended toward Johnstown it picked up trees, houses, a viaduct, railroad cars, and a wire works with miles of barbed wire that entangled everything that fell in the water. Fifty died in East Conemaugh and three hundred fourteen in Woodvale. Fifty-eight minutes after busting the dam, the torrent reached Johnstown — sixty feet high, travelling at forty miles per hour and with the force of the Mississippi River at the delta.
Debris above Pennsylvania Railroad bridge
A seventy-foot-high pile of debris stuck at the Pennsylvania Railroad stone bridge and caught fire, immolating all who had been swept into the crush. A second wave of water and debris rushed into town from another direction, catching survivors of the first wave by surprise. Before the waters subsided, more than two thousand two hundred people were dead. The thirty-acre jam at the bridge had to be dynamited and it took three months to clear it all out. More than seven hundred of the dead were never identified.