Item: IS ARCTIC SNOW DIFFERENT FROM ALPINE SNOW? DELVING INTO THE COMPLEXITIES OF SNOW COVER PROPERTIES AND SNOW INSTABILITY
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Title: IS ARCTIC SNOW DIFFERENT FROM ALPINE SNOW? DELVING INTO THE COMPLEXITIES OF SNOW COVER PROPERTIES AND SNOW INSTABILITY
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Alec van Herwijnen [ WSL Institute for Snow and Avalanche Research SLF ]
Date: 2024-09-23
Abstract: Assessing snow instability is fundamental in avalanche forecasting. In the past, snow instability was seen as a balance between weak layer shear strength and the overlying load (slab and perhaps a skier). Nowadays, we recognize that this was an oversimplification. Snow instability is best understood in terms of the complex interplay between snow stratigraphy and external loading, influencing the fundamental processes of failure initiation and crack propagation. In short, an avalanche is triggered when a locally initiated failure propagates through a buried weak layer across the slope. While the basic concepts of avalanche release are relatively well understood, there is still no unified physics-based model that can be used for practical applications. Hence, machine learning models were developed to assess snow instability. Most of our knowledge on snow stability as well as the models we use for stability assessments come from alpine snow covers, i.e. mid-latitude mountainous regions with seasonal snow covers, such as in the European Alps or in North America. This raises pertinent questions regarding the transferability of these approaches to Arctic regions. Is snow simply snow, or does Arctic snow possess its own secrets? Arctic snowpacks present unique challenges due to distinct boundary conditions, notably the absence of solar radiation during winter months and the frozen ground. These widely different boundary conditions affect internal snowpack processes with mostly unknown repercussions on snow stability. We therefore use the snow cover model SNOWPACK to explore the transferability of a recently established machine learning model to assess snow stability from alpine to Arctic contexts. First, we assess the viability of our model approach in Arctic regions by comparing stability predictions with local avalanche observations. Subsequently, we undertake a comparative analysis of modelled stability patterns between the Alps and the Arctic, scrutinizing differences and seeking to unravel the essence of Arctic snow stability.
Object ID: ISSW2024_O3.1.pdf
Language of Article: English
Presenter(s): Alec van Herwijnen
Keywords: Snow stability, weak layers, avalanche activity, arctic
Page Number(s): 401 - 408
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