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Geologic Publications for Mount Rainier

Rockfalls and avalanches from Little Tahoma Peak on Mount Rainier Washington

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Author(s): Dwight R. Crandell, Robert K. Fahnestock

Document Type: Bulletin 1221-A
Publisher: United States Geological Survey
Published Year: 1965
Pages: 37
DOI Identifier:
ISBN Identifier:

In December 1963 rockfalls from Little Tahoma Peak on the east side of Mount Rainier fell onto Emmons Glacier and formed avalanches of rock debris that traveled about 4 miles down the glacier and the White River valley. In this distance, the rock debris descended as much as 6,200 ft in altitude. Minor lithologic differences and crosscutting relations indicate that the rockfalls caused at least seven separate avalanches, having an estimated total volume of 14 million cubic yards. The initial rockfall may have been caused by a small steam explosion near the base of Little Tahoma Peak.

During movement, some of the avalanches deflected from one side of the valley to the other. Calculations based on the height to which the avalanches rose on the valley walls suggest that their velocity reached at least 80 or 90 miles per hour. The unusually long distance some of the avalanches were transported is attributed to a cushion of trapped and compressed air at their base, which buoyed them up and reduced friction.

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Suggested Citations:
In Text Citation:
Crandell and Fahnestock (1965) or (Crandell and Fahnestock, 1965)

References Citation:
Crandell, D.R. and R.K. Fahnestock, 1965, Rockfalls and avalanches from Little Tahoma Peak on Mount Rainier Washington: Bulletin 1221-A, United States Geological Survey, 37 p..