Item: Modelled mass and temperature effects of entrained snow on the lubricated flow regime and implications for predicting avalanche runout distance
-
-
Title: Modelled mass and temperature effects of entrained snow on the lubricated flow regime and implications for predicting avalanche runout distance
Proceedings: International Snow Science Workshop Proceedings 2018, Innsbruck, Austria
Authors:
- Katreen Wikstrom Jones [ Alaska Division of Geological & Geophysical Surveys, Fairbanks, AK, USA ] [ Department of Environmental Science, Alaska Pacific University, Anchorage, AK, USA ]
- Michael Loso [ Department of Environmental Science, Alaska Pacific University, Anchorage, AK, USA ] [ Wrangell-St. Elias National Park and Preserve, Copper Center, AK, USA ]
- Perry Bartelt [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
Date: 2018-10-07
Abstract: Understanding how the snow cover in an avalanche path may impact avalanche flow behavior is essential to predict an accurate avalanche runout. In avalanche paths with strong elevational snow temperature gradients it is common for multiple flow regimes to develop within one avalanche. We demonstrate the role of snow entrainment for the development of fluidized and lubricated flow regimes and their effects on avalanche runout. We simulated avalanches in the avalanche runout model RAMMS on a 2 m resolution digital elevation model of a long, continuous, 30° (average) avalanche slope in maritime south-central Alaska, to examine how mass and temperature of released and entrained snow affect the lubricated wet flow regime and therefore avalanche runout distances. We found that meltwater production was the predominant contributing factor to long runout distances due to reduced basal friction as the avalanche makes the transition from the fluidized to the lubricated flow regime. The temperature of entrained snow was most important when the entrained mass was large relative to the released mass, and small increases in snow temperature (e.g. from -3°C to -1°C) could drastically enhance avalanche runout. Based on our results, we suggest that avalanche forecasters working in subarctic climates closely monitor warming snow cover temperatures, especially during weather events that could rapidly warm the snow, e.g., rain or strong solar radiation during the spring months.
Language of Article: English
Presenters:
Keywords: Snow Entrainment, Avalanche Runout, Flow Regime, Fluidization, Lubrication.
Page Number(s): 84-88
-
Digital Abstract Not Available
-