International Snow Science Workshop Proceedings - Montana State University Library

Item: Snow Slope Stability Evaluation Using Concepts of Fracture Mechanics

• • Title: Snow Slope Stability Evaluation Using Concepts of Fracture Mechanics

    Proceedings: Proceedings of the 2006 International Snow Science Workshop, Telluride, Colorado

    Authors:

    • Jürg Schweizer  [ WSL Swiss Federal Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
    • Ian McCammon  [ SnowPit Technologies, Salt Lake City UT, U.S.A ]
    • J. Bruce Jamieson  [ Department of Civil Engineering, Department of Geophysics and Geology, University of Calgary, Calgary AB, Canada ]

    Date: 2006

    Abstract: Dry snow slab avalanche release is generally believed to proceed in three stages: 1) initiation of a local failure, 2) widespread propagation of that fracture beneath the slab, and 3) detachment of the slab from its margins. To date, most field stability tests primarily assess the strength of the weak layer and thus relate to the first stage of avalanche release – fracture initiation. But field methods that comprehensively evaluate the second stage – fracture propagation – have remained elusive. In this paper, we explore evidence that field estimates of stability can be improved by integrating three elements: test score, fracture character or release type, and a simple index of structural stability (the threshold sum or “lemon count” across the fracture interface). Using field data collected from skier triggered avalanches and skier tested slopes that did not release, we show that when these three elements fall into a critical range the accuracy of predicting the probability of a skier triggered avalanche is higher than when any one element is used alone. Further, we show through a qualitative analysis that these three elements fulfill, at least partially, the criteria for fracture propagation prior to avalanching. As with any field stability method that relies on localized snowpack data, the approach presented here is not intended to be used in isolation, but in conjunction with other measurements and observations that relate to the probability and consequences of avalanche release.

    Object ID: issw-2006-211-218.pdf

    Language of Article: English

    Presenter(s): Unknown

    Keywords: snow stability evaluation, avalanche formation, avalanche release, skier triggering, stability test, fracture

    Page Number(s): 211-218

    Subjects: snow stability snow fracture avalanche release

  • Get Full Article

Back to Home page