Historic rockfall avalanches, northeastern Glacier National Park, Montana
Butler DR, Oelfke JG, Oelfke LA. 1986. Historic rockfall avalanches, northeastern Glacier National Park, Montana. Mountain Research and Development. :11
Two large rockfall avalanches have occurred within the last 100 years in GNP, both associated with the eastern edge of the Lewis Overthrust Fault. Historical documents, maps, and photographs provide bracketing dates of 1902-1914 and 1936-1966 for the two events while tree-ring data indicate that older rockfall avalanche occurred in 1910, and the younger one in 1954. The 1910 rockfall avalanche occurred after a local cloudburst, but the immediate cause of the 1954 event has not been determined. Until recently, all naturally-occurring, high-magnitude rockfall-avalanche deposits in the Rocky Mountains were thought to be of considerable age. The recent age of the rockfall avalanches reported here, combined with the speed and the terrain susceptible to mass movements, suggest that proposed developments in the area must be critically examined in light of the potential for similar catastrophic slope failure.
- Type
- Journal Article
- Authors
- Butler, David; Oelfke, Jack; Oelfke, Lori
- Units
- CRCO , GLAC
- Keywords
- avalanche, Geology, Hazard, Hazard environment, Landslide, Rockfall