Item: Surface Warming of a Dry Snowpack Increases Skier-Induced Stress and Strain Magnitudes in Deeper Weak Layers
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Title: Surface Warming of a Dry Snowpack Increases Skier-Induced Stress and Strain Magnitudes in Deeper Weak Layers
Proceedings: Proceedings of the 1998 International Snow Science Workshop, Sunriver, Oregon
Authors:
- A. Wilson [ Department of Civil Engineering, University of Calgary, Calgary, Alberta, Canada ]
- J. Schweizer [ Swiss Federal Institute for Snow and Avalanche Research, Davos Dorf, Switzerland ]
- C.D. Johnston [ Department of Civil Engineering, University of Calgary, Calgary, Alberta, Canada ]
- J.B. Jamieson [ Department of Civil Engineering, University of Calgary, Calgary, Alberta, Canada ]
Date: 1998
Abstract: Changes in air temperature, and hence snow temperature, influence snow stability for skiers. This paper studies how warming in the top 20 cm of a hard 'spring' like snowpack and a softer 'mid-winter' like snowpack influence the stresses and strains due to a skier load in weak layers 30 cm and 50 cm below the surface. The temperature effects are studied using a finite element model to predict how the load is transferred through a layered snowpack. The results show that the warming front does not have extend into the weak layer to have an effect. As the stiffness of the top slab is reduced, the peak stress and peak strain increase in the weak layers. The 30 cm weak layer was more effected by the skier load than the 50 em layer with an increase in shear stress of 8% in the mid-winter snowpack model and 51% in the spring snowpack model. A model of a real snowpack with a surface wind slab again Subject to a skier load showed an increase in shear stress of 32% when a weak layer was present at 22 em and the top 19 cm was warmed. The increase in stress and strain in the weak layer in all models support the argument that there will be increase in the likelihood of skier-induced avalanche after warming.
Language of Article: English
Presenters: Unknown
Keywords: snow stability, avalanche triggering, snow thermal effects
Page Number(s): 514-519
Subjects: avalanche triggering snow stability temperature environment
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Digital Abstract Not Available
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