Item: NEW INSIGHTS OF MECHANICAL SNOWPACK PROPERTIES MEASURED BY ACOUSTIC AND SEISMIC DISTRIBUTED FIBER OPTIC SENSING
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Title: NEW INSIGHTS OF MECHANICAL SNOWPACK PROPERTIES MEASURED BY ACOUSTIC AND SEISMIC DISTRIBUTED FIBER OPTIC SENSING
Proceedings: Proceedings, International Snow Science Workshop, Whistler, BC, Canada, 2026
Authors:
- Alexander Prokop [ University of Vienna, Vienna, Austria ] [ Snow Scan GmbH, Vienna, Austria ]
- Nicola Agostinetti [ University of Vienna, Vienna, Austria ] [ Dipartimento di Scienze dell'Ambiente e della Terra, Università di Milano Bicocca, Milano, Italia ]
- Benedikt Anwander [ University of Vienna, Vienna, Austria ]
- Bernhard Grasemann [ University of Vienna, Vienna, Austria ]
Date: 2026-09-28
Abstract: Since 2012 we successfully monitor avalanche activity using distributed seismic fiber optic sensing at our avalanche test area at Lech am Arlberg, Austria. We now focused on measuring mechanical snow pack properties utilizing a unique measurement set-up, where a fiber optic cable was inserted in a weak layer, near the snow surface and at the ground/snow interface. For the first time it was possible to measure and analyze the collapse of a weak layer in an avalanche release area. On February 14th we inserted the fiber optic cable within the snow pack and after a major snowfall a slab was formed and the weak layer collapsed on February 17th in the middle of the night with consecutive two small avalanche events happening. We could measure the collapse of the weak layer on a section of 250 m along the cable with a speed between 25 and 100 m/s corresponding to values found in literature. As the fiber optic cable was located close to the snow surface we were also able to measure strong winds affecting the snow surface and we see that early in the morning of February 17th strong gusts most likely triggered mechanically small avalanches. Furthermore we are able to locate strong wind patterns such as turbulence and linear wind flows along a length of 300 m along the cable and the data of the whole winter season correlated with wind speed and direction data that is available on site leads us to question current snow drift models and we indicate possible improvements that can be made using our data. Finally we are also able to see skiers moving along our cable and we are able to analyze their behavior in regard of avalanche safety measures. We can see at what time and how many and most importantly in what distance to each other those skiers crossed the avalanche prone slope. In a time of unstable snow pack stability conditions we conclude that not all skiers follow the recommended safety rules and our data is very useful for analyzing different mechanical snow pack properties and processes.
Object ID: ISSW2026_O1.5.pdf
DOI: https://doi.org/10.15788/1790098479
Language of Article: English
Presenter(s): Alexander Prokop
Keywords: distributed seismic sensing, fiber optic, weak layer collapse, mechanical properties
Page Number(s): 1481 - 1487
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