Item: The spatial and temporal variability of slab hardness
Title: The spatial and temporal variability of slab hardness
Proceedings: Proceedings of the 2000 International Snow Science Workshop, October 1-6, Big Sky, Montana
Authors: Mark Kozak, Department of Earth Resources, Colorado State University, Fort Collins, Colorado Kelly Elder Rocky Mountain Research Station, U.S. Forest Service, Fort Collins, Colorado Karl Birkeland Forest Service National Avalanche Center, Bozeman, Mo
Abstract: A slab avalanche occurs when a weak layer or interface below the slab fractures, causing the slab to release. A large percentage of accidents associated with slab avalanches result when the victim triggers the release. While it is recognized that avalanches are caused by the unique interaction between the weak layer and the slab, most research has focused on the composition of the weak layer and how its strength changes over time. Relatively few studies have examined how slab properties change over time and space. We expect slab properties to change over time and space because of both the inherent variations in the energy balance associated with aspect and the dependency of snow metamorphism on the energy balance. This research attempts to address the following research question: to what degree does slab hardness vary with aspect and time when elevation and slope are kept relatively constant? Slab hardness was measured with a ram penetrometer on north and south aspects from January through March, 2000 at Jackson Hole Mountain Resort and Grand. Teton National Park, WY. While hardness increased more rapidly on southern than northern aspects due to settlement and densification, solar radiation on southern aspects also contributed to greater heterogeneity in the snowpack.
Keywords: hardness, new snow-layer, incoming shortwave radiation, maximum daily temperature
Digital Abstract Not Available