Item: Automatic Dynamic Avalanche Modeling - An example of its application in an operational setting in Norway
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Title: Automatic Dynamic Avalanche Modeling - An example of its application in an operational setting in Norway
Proceedings: International Snow Science Workshop Proceedings 2018, Innsbruck, Austria
Authors:
- Cesar Vera [ Wyssen Avalanche Control, Reichenbach, Switzerland ]
- Nander Wever [ Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder CO, USA ]
- Stian Langeland [ Wyssen Avalanche Control, Reichenbach, Switzerland ]
- Leif Øyvind [ Wyssen Avalanche Control, Reichenbach, Switzerland ]
Date: 2018-10-07
Abstract: The county road Fv. 53 at Tyin (Norway) is an important road for the inner parts of the Sogn region and especially the local community in Ã…rdal. In winter time, it is regularly exposed to avalanche hazards. An operational avalanche control service is present, which includes daily avalanche forecasts and using remote avalanche control systems (RACS). To support the local forecasting team, a model chain has been developed and implemented in which numerical snowpack modelling is coupled to avalanche dynamics simulations to assess avalanche risks. The primary system output is an assessment of snow cover stability as well as avalanche size and runout. Based on measurements from automatic weather stations, the temporal evolution of the snowpack is simulated using the SNOWPACK model. The SNOWPACK model provides snowpack stability estimates and, based on the weak layer depth, potential fracture depths and snowpack properties of the slab. The spatially distributed model Alpine3D allows to account for complex terrain features such as radiation effects. This information is used to provide the initial conditions for the avalanche dynamics model RAMMS for predetermined avalanche paths. The model chain was run for 14 different avalanche paths which could affect the 9 km road section at Tyin and are relevant for the operational forecasting. Around 100 avalanches were triggered using the installed RACS in the winters 2016/17. This dataset was used to verify and calibrate the models. As wind drift is a major challenge in the Tyin operation, new algorithms were tested to account for wind transport. The properties of the entrained snow, which is an important factor to determine avalanche runout, are also accounted for. The system in which real-time snow cover simulations are combined with avalanche dynamics simulations is a novel approach to provide avalanche forecasters with a new source of objective information to support the avalanche control team in their decision making and risk management.
Object ID: ISSW2018_P08.7.pdf
Language of Article: English
Presenter(s):
Keywords: numeric modeling, avalanche dynamics, snowcover modeling, risk assessment.
Page Number(s): 746-750
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