Item: High Resolution Tree-Ring Based Spatial Reconstructions of Snow Avalanche Activity in Glacier National Park, Montana, USA
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Title: High Resolution Tree-Ring Based Spatial Reconstructions of Snow Avalanche Activity in Glacier National Park, Montana, USA
Proceedings: Proceedings of the 2006 International Snow Science Workshop, Telluride, Colorado
Authors:
- Gregory T. Pederson [ U.S. Geological Survey – Northern Rocky Mountain Science Center, West Glacier, MT ] [ Big Sky Institute – Montana State University, Bozeman, MT ]
- Blase A. Reardon [ U.S. Geological Survey – Northern Rocky Mountain Science Center, West Glacier, MT ]
- Christian J. Caruso [ U.S. Geological Survey – Northern Rocky Mountain Science Center, West Glacier, MT ] [ Big Sky Institute – Montana State University, Bozeman, MT ]
- Daniel B. Fagre [ U.S. Geological Survey – Northern Rocky Mountain Science Center, West Glacier, MT ]
Date: 2006
Abstract: Effective design of avalanche hazard mitigation measures requires long-term records of natural avalanche frequency and extent. Such records are also vital for determining whether natural avalanche frequency and extent vary over time due to climatic or biophysical changes. Where historic records are lacking, an accepted substitute is a chronology developed from tree-ring responses to avalanche-induced damage. This study evaluates a method for using tree-ring chronologies to provide spatially explicit differentiations of avalanche frequency and temporally explicit records of avalanche extent that are often lacking. The study area - part of John F. Stevens Canyon on the southern border of Glacier National Park – is within a heavily used railroad and highway corridor with two dozen active avalanche paths. Using a spatially geo-referenced network of avalanche-damaged trees (n=109) from a single path, we reconstructed a 96-year tree-ring based chronology of avalanche extent and frequency. Comparison of the chronology with historic records revealed that trees recorded all known events as well as the same number of previously unidentified events. Kriging methods provided spatially explicit estimates of avalanche return periods. Estimated return periods for the entire avalanche path averaged 3.2 years. Within this path, return intervals ranged from ~2.3 yrs in the lower track, to ~9-11 yrs and ~12 to >25 yrs in the runout zone, where the railroad and highway are located. For avalanche professionals, engineers, and transportation managers this technique proves a powerful tool in landscape risk assessment and decision making.
Language of Article: English
Presenters: Unknown
Keywords: avalanche history, tree-rings, kriging, return periods
Page Number(s): 436-443
Subjects: snow avalanche tree-ring spatial reconstructions
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Digital Abstract Not Available
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