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Castle Lake formed as a result of the Mount St. Helens' May 18, 198...

Detailed Description

The May 18, 1980 debris avalanche from Mount St. Helens covered over 24 square miles (62 square kilometers) of the upper Toutle River valley and blocked tributaries of the North Fork Toutle River. New lakes such as Castle Lake (pictured here) and Coldwater Lake were created.


Public Domain.