Rapid Geomorphic Change Caused by Glacial Outburst Floods and Debris Flows along Tahoma Creek, Mount Rainier, Washington, USA
Walder JS and Driedger CL. 1994. Rapid Geomorphic Change Caused by Glacial Outburst Floods and Debris Flows along Tahoma Creek, Mount Rainier, Washington, USA. Arctic and Alpine Research. 26(4):319-327
As part of a hazards assessment study, we examined the nature and rate of geomorphic change caused by outburst floods and debris flows along Tahoma Creek, Mount Rainier, since 1967. Archival aerial photos of the area proved to be a rich source of qualitative geomorphic information. On the basis of limited direct evidence and considerations of stream hydrology, we conclude that nearly all of these debris flows began as ouburst floods from South Tahoma Glacier. The water floods transformed into debris flows by incorporating large masses of sediment in a 2-km-long channel reach where the stream has incised proglacial sediments and debris-rich, stagnant glacier ice. Comparison of topographic maps for 1970 and 1991 shows that the average sediment flux out of the incised reach has been about 2 to 4 x 10 (5) cubic meters a(-1), corresponding to an average denudationr ate in the upper part of the Tahoma Creek drainage basin of about 20-40 mm a(-1), a value exceeded only rarely in basins affected by debris flows. However, little of this sediment has yet passed out of the Tahoma Creek basin. Comparison of geomorphic change at Tahoma Creek to that in two other alpine basins affected by outburst floods suggests that debris rich stagnant ice can be an important source of sediment for debris flows as long as floods are frequent or channel slope is great.
- Type
- Journal Article
- Authors
- Walder, Joseph; Driedger, Carolyn
- Units
- MORA
- Keywords
- Debris Flows, Geology, glacial outburst floods, Hydrology, Nisqually glacier Mount Rainier National Park WA, Nisqually River Mount Rainier National Park WA, Physical Sciences, South Tahoma Glacier, stagnant glacial ice, Tahoma Creek, Tahoma Creek bridge Mount Rainier National Park WA, Tahoma glacier Mount Rainier National Park WA, Wonderland Trail Mount Rainier National Park WA