Item: Near Surface Faceted Crystals: Conditions Necessary for Growth and Contribution to Avalanche Formation, Southwest Montana, U.S.A.
-
-
Title: Near Surface Faceted Crystals: Conditions Necessary for Growth and Contribution to Avalanche Formation, Southwest Montana, U.S.A.
Proceedings: Proceedings of the 1996 International Snow Science Workshop, Banff, Canada
Authors:
- Karl Birkeland [ Gallatin National Forest Avalanche Center, P.O. Box 130, Bozeman, MT 59771 ] [ Department of Geography, Arizona State University, Tempe, AZ. 85287-0104 ]
- Ron Johnson [ Gallatin National Forest Avalanche Center, P.O. Box 130, Bozeman, MT 59771 ]
- Scott Schmidt [ Department of Civil and Agricultural Engineering, Montana State University, Bozeman, MT 59717 ]
Date: 1996
Abstract: In the winter of 1995-96 we investigated the formation of faceted crystals that develop in the upper levels of the snowpack. We used an array of six thermocouples connected to a datalogger to measure hourly diurnal temperature changes in the region from 0.005 m above the snow surface to 0.20 m below the snow surface. Measurements during clear sky conditions in March showed temperature gradients in excess of 2000 C/m at night in the top 0.05 m of the snowpack, with the temperature gradient shifting direction and exceeding 1000 C/m through this layer during the day. A significant weak layer of faceted snow formed within 36 hours with a grain size of about 1 mm in the upper snowpack. Widespread avalanche activity occurred for up to nine days after this layer was buried by 0.50 m of snow.
Object ID: issw-1996-075-080.pdf
Language of Article: English
Presenter(s): Unknown
Keywords: avalanche, snow metamorphism, faceted crystals, temperature gradient
Page Number(s): 75-80
Subjects: snow metamorphism temperature gradients faceted crystals
-