Geologic Publications for Mount Rainier
Frequent outburst floods from South Tahoma Glacier, Mount Rainier, U.S.A.: Relation to debris flows, meterological origin and implications for subglacial hydrology
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Joseph S. Walder
, Carolyn L. Driedger
Journal of Glaciology
Destructive debris flows occur frequently at glacierized Mount Rainier volcano, Washington, U.S.A. Twenty-three such flows have occurred in the Tahoma Creek valley since 1967. Hydrologic and geomorphic evidence indicate that all or nearly all of these flows began as outburst floods from South Tahoma Glacier. Flood waters are stored subglacially. The volume of stored water discharged during a typical outburst flood would form a layer several centimeters thick over the bed of the entire glacier, although it is more likely that large linked cavities account for most of the storage. Statistical analysis shows that outburst floods usually occur during periods of atypically hot or rainy weather in summer or early autumn, and that the probability of an outburst increase with temperature (a proxy measure of ablation rate) or rainfall rate. We suggest that outburst floods are triggered by rapid water input to the glacier bed, causing water-pressure transients that destabilize the linked-cavity system. The correlation between outburst floods and meteorological factors casts doubt on an earlier hypothesis that melting around geothermal vents triggers outburst floods from South Tahoma Glacier.
In Text Citation:
Walder and Driedger (1995) or (Walder and Driedger, 1995)
Walder, J.S. and C.L. Driedger, 1995, Frequent outburst floods from South Tahoma Glacier, Mount Rainier, U.S.A.: Relation to debris flows, meterological origin and implications for subglacial hydrology: Journal of Glaciology, Vol. 41, No. 137, 11 p..