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Today in History: Johnstown Flood: Six Dams Fail, 84 Lives Lost

7/20/2025

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Summary

Story summary

On July 19, 1977, a stalled thunderstorm unleashed heavy rainfall in Cambria County, Pennsylvania, leading to the failure of six dams. The resulting flood devastated Johnstown and the Conemaugh Valley, claiming 84 lives and causing $340 million in damages. This disaster marked one of the most significant floods in the region's history.

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Story summary

On July 19, 1977, a stalled thunderstorm unleashed heavy rainfall in Cambria County, Pennsylvania, leading to the failure of six dams. The resulting flood devastated Johnstown and the Conemaugh Valley, claiming 84 lives and causing $340 million in damages. This disaster marked one of the most significant floods in the region's history.