The South Fork Dam was completed in 1853 as a chiefly earthen dam built in thin layers of clay that were puddled with water to help them settle and harden, with stone-faced slopes and five large outlet pipes installed beneath it to discharge water safely. Its only original inadequacy was a spillway that was too small, but although it was well engineered for its time, years of neglect and unsound alterations made it unsafe. By 1889, the water control tower had burned down and the iron outlet pipes had been removed, making it impossible to control the lake level. Earlier breaches had been improperly filled with stone, dirt, brush, and manure, the center had settled and sagged, inviting a washout, and fish screens had reduced the spillway's capacity to handle overflow. On May 31, 1889, rising floodwaters forced the dam to give way, and the resulting flood wave thundered 14 miles downstream to Johnstown, killing more than 2,200.

Photo: William Fischer, Jr.

Photo: William Fischer, Jr.

Photo: William Fischer, Jr.

Photo: William Fischer, Jr.

Photo: William Fischer, Jr.

Photo: William Fischer, Jr.

Photo: William Fischer, Jr.

Croyle, Pennsylvania · USA