Geologic Publications for Mount Rainier
Glacier outburst floods at Mount Rainier, Washington state, U.S.A.
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Carolyn L. Driedger
, Andrew G. Fountain
Annals of Glaciology
51 to 55
During the twentieth century, glacial outburst floods have been the most destructive natural events on Mount Rainier, a stratovolcano in the Cascade Range in Washington State, U.S.A. In the period between 1930 and 1980, numerous floods were reported from five glaciers on the mountain, most of which flowed from Nisqually, Kautz or South Tahoma Glaciers on its southern flank. Such floods threaten lives and property because they occur without warning and quickly mobilize the loose volcanic debris into debris flows.
A monitoring program was begun in 1987 which was designed to measure the dimensions and timing of outburst floods, but this has been unsuccessful because no flood have yet occurred on the monitored streams. Four floods did burst from South Tahoma Glacier that went unmonitored, but in spite of this they have been useful in providing evidence of flood storage and release mechanisms. All flood volumes were found to be of approximately similar orders of magnitude, of 1x105
of water, indicating that all floods probably had similar mechanisms for storage and release of water. Hydraulic pressure considerations indicate that such a large volume of flood water would be stored at the bed of the glacier rather than in isolated englacial cavities. The stepped bedrock terrain provides an ideal setting for the formation of subglacial cavities capable of storing the volumes of flood water noted.
In Text Citation:
Driedger and Fountain (1989) or (Driedger and Fountain, 1989)
Driedger, C.L. and A.G. Fountain, 1989, Glacier outburst floods at Mount Rainier, Washington state, U.S.A.: Annals of Glaciology, Vol. 13, pp. 51-55.