Item: Tracking changes in buried melt freeze crusts
Title: Tracking changes in buried melt freeze crusts
Proceedings: International Snow Science Workshop, Davos 2009, Proceedings
Authors: Michael Smith and Bruce Jamieson, Dept. of Civil Engineering, University of Calgary, Calgary, AB Dept. of Geoscience, University of Calgary, Calgary, AB
Abstract: Melt freeze crusts are a frequent occurrence in the mid-latitudes, often forming in the snowcover due to rain or wet snow in the fall and insolation in the spring. Such crusts are frequently found at the bed surface of deep slab avalanches. Although faceting and weakening at the boundaries and in the interior of crusts under low temperature gradients has been documented, few long term systematic observations exist. This omission is potentially important, as an understanding of these processes may improve forecasting the strength of deep crusts. For the past two winter seasons, the University of Calgary Applied Snow and Avalanche Research group (ASARC) has monitored naturally occurring crusts in the Columbia Mountains of Western Canada. Properties such as grain form and size, density, temperature and hardness were observed on a weekly basis. Starting in the 2008-09 field season, the specific surface area (SSA) of three crusts was measured weekly using near infrared digital photography, resulting in 23 observations over two months including the transition to near-isothermal snow, where substantial structural changes were observed. This paper details these and other results.
Keywords: specific surface area, crust evolution, near-infrared photography, snowpack stratigraphy
Digital Abstract Not Available