Downstream view of the North Fork Toutle River valley, north and west of St. Helens, shows part of the nearly 2/3 cubic miles ( cubic kilometers) of debris avalanche that slid from the volcano on May 18, 1980. This is enough material to cover Washington, to a depth of 14 feet (4 meters). The avalanche traveled approximately 15 miles (24 kilometers) downstream at a velocity exceeding 150 miles per hour (240 km/hr). It left behind a hummocky deposit with an average thickness of 150 feet (45 meters) and a maximum thicknes of 600 feet (180 meters).
Downstream view of the North Fork Toutle River valley, north and west of St. Helens, shows part of the nearly 2/3 cubic miles ( cubic kilometers) of debris avalanche that slid from the volcano on May 18, 1980. This is enough material to cover Washington, to a depth of 14 feet (4 meters). The avalanche traveled approximately 15 miles (24 kilometers) downstream at a velocity exceeding 150 miles per hour (240 km/hr). It left behind a hummocky deposit with an average thickness of 150 feet (45 meters) and a maximum thicknes of 600 feet (180 meters).
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Photo credit: © CPC Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: .., 14, 18, 1980., avalanche, cover, debris, depth, feet, material, slid, volcano, washington
