Hydrologic and biologic consequences of an avalanche striking an ice-covered lake
Title | Hydrologic and biologic consequences of an avalanche striking an ice-covered lake |
Publication Type | Conference Proceedings |
Year of Conference | 1990 |
Authors | Williams, M. W., and Clow D. W. |
Conference Name | 58th Annual Western Snow Conference |
Series Title | Proceedings of the 58th Annual Western Snow Conference |
Date Published | April 1990 |
Publisher | Western Snow Conference |
Conference Location | Sacramento, California |
Keywords | Avalanche, Flood, Lake, Snow, Trout |
Abstract | The hydrological and biological effects of large avalanches striking ice-covered lakes have rarely been documented, due to the extreme weather conditions, remote locations and hazards often associated with these events. Here we report the effects of a large avalanche striking ice-covered Emerald Lake on February 17, 1986. The lake is located at an elevation of 2800 meters, in the southern Sierra Nevada, California. The avalanche, traveling about 20 m/sec, struck the lake with a force of 2.12x10(6) N. About 70% of the unfrozen water (90,000) m(3) in the lake was displaced into the outlet stream. The floodwave in the lake's outflow removed 5.4x10(5) kg of snow from the channel. Scouring of the streambed was observed throughout the exposed reach. The survival rate of embryos and sac fry from the resident brook trout (Salvelinus fortinalis), in the lake's outlet, decreased from close to 90% before the flood to 2.5% after the flood. |
URL | sites/westernsnowconference.org/PDFs/1990Williams.pdf |