Item: Variations of Snow Instability Seen From a Bird's Eye
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Title: Variations of Snow Instability Seen From a Bird's Eye
Proceedings: International Snow Science Workshop 2016 Proceedings, Breckenridge, CO, USA
Authors:
- Benjamin Reuter [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ]
- Jürg Schweizer [ WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland ]
Date: 2016-10-02
Abstract: The layering of the seasonal snowpack resembles an archive of the season's meteorological history. Whereas at the mountain range scale mainly meteorological processes drive the variations, at the basin scale and below interactions with terrain become more influential and complex. With recent developments in measurement and analysis techniques, the previous difficulties in measuring, mapping and interpreting the observed variations can be overcome. We analyzed five campaigns in a small basin above Davos (eastern Swiss Alps) from the seasons between 2011 and 2013. The data cover five different avalanche situations and contain snow pit data plus about 750 spatially distributed snow micro-penetrometer profiles. From those profiles observer-independent measures of snow instability were derived, which agreed well with in-situ stability observations. We then analyzed the spatial variability seen among these measures of snow instability within our sampling area (≈0.2 km) and produced the first maps of basin scale instability variations. Whereas, on these maps some variability was apparently due to terrain and snow depth variations, the more complex couplings of micro-meteorological processes with terrain could only be identified with distributed snowpack simulations using Alpine3D. Causes of snow instability varied between the five avalanche situations, but still, slope aspect was the most prominent driver. According to the snowpack simulations, for one selected day, the micro-meteorological forcing was due to the preferential deposition of precipitation and the surface energy input. The obtained auto-correlation ranges suggest that in our sampling area small scale variations were rather due to micro-meteorological forcing than to terrain parameters or snow depth. We show how meteorological forcing causes variations of snow instability, and suggest a way to validate spatial snowpack simulations before operational use.
Object ID: ISSW16_O11.03.pdf
Language of Article: English
Presenter(s):
Keywords: snow micro-penetrometer, spatial variability, snow instability, geostatistical modeling, snow cover modeling
Page Number(s): 262-265
Subjects: snow micro penetrometer spatial variability snow cover model
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