High resolution tree-ring based spatial reconstructions of snow avalanche activity in Glacier National Park, Montana, USA

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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.

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Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title High resolution tree-ring based spatial reconstructions of snow avalanche activity in Glacier National Park, Montana, USA
Year Published 2006
Language English
Contributing office(s) Northern Rocky Mountain Science Center
Description 8 p.
Larger Work Type Conference Paper
Larger Work Subtype Conference Paper
Larger Work Title Proceedings of 2006 International Snow Science Workshop
First page 436
Last page 443
Conference Title 2006 International Snow Science Workshop
Conference Location Telluride, CO
Conference Date October 1-6, 2006
Country United States
State Montana
Other Geospatial Glacier National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N