Our
Beautiful World
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Debris avalanche and flow / Skred eller
flom av løst materiale
Downstream view of the North Fork Toutle River valley, north and west of St. Helens, shows part of the nearly 2/3 cubic miles (2.3 cubic kilometers) of debris avalanche that slid from the volcano on May 18, 1980. 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). USGS Photograph taken on November 30, 1983, by Lyn Topinka. |
Debris flow: |
Debris flom: En blanding av vanntrukkene steinrester |
ANIMALS over 250 |
BIRDS over 500 |
FLOWERS over 225 |