It started raining on Memorial Day 1889, and it would not stop. High in the hills above Johnstown, Pennsylvania, an old earth dam held back a private lake used by a fancy fishing club. By the afternoon of May 31, water was pouring over the top. At 3:10 p.m., the South Fork Dam gave way and twenty million tons of water - a wall almost forty feet high - came roaring down the valley toward the steel town below.
The flood traveled fourteen miles in under an hour, picking up trees, train cars, houses, and a tangle of barbed wire from a wire factory. In Johnstown, families heard a sound like thunder before the wave hit. Whole neighborhoods were swept downstream and slammed into a stone railroad bridge, where the debris caught fire. By morning, 2,209 people were gone, and the town looked like it had been chewed up. The newspapers called it the worst disaster America had ever seen.
The response changed history. A young nurse named Clara Barton arrived with her brand-new American Red Cross - it was the group's first big peacetime mission, and they stayed for five months handing out food, blankets, and tents. Engineers also learned hard lessons about how to build dams safely. Johnstown was rebuilt, flooded twice more in the 1900s, and still stands today. A quiet stone marker now sits where the old dam used to be, watching over the empty valley.
