Item: ARCTIC MOUNTAIN GLACIERS LOVE AVALANCHES
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Title: ARCTIC MOUNTAIN GLACIERS LOVE AVALANCHES
Proceedings: International Snow Science Workshop 2024, Tromsø, Norway
Authors:
- Alexander Prokop [ University Vienna ] [ Snow Scan GmbH ]
- Bernhard Hynek [ Geosphere Austria, Department Climate Impact Research ]
- Eric Bernard [ ThéMA CNRS, Université de Franche Comté ]
- Signe Hillerup Larsen [ Geological Survey of Denmark and Greenland ]
- Florian Tolle [ ThéMA CNRS, Université de Franche Comté ]
- Jean-Michel Friedt [ FEMTO-ST CNRS, Université de Franche Comté ]
Date: 2024-09-23
Abstract: At ISSW and in general avalanches are usually discussed in the context of a natural hazard that harms people and infrastructure and needs to be managed to avoid disasters. On the contrary this presentation focuses on a positive effect of avalanches at least if we are worried that glaciers are melting fast due to climate warming. In recent years glacier mass balance is calculated according to high resolution geodetic mass balance measurements via LiDAR and/or SfM-photogrammetry that cover the whole glacier surface in sub-meter resolution. Those methods allow for determining precisely the influence that avalanches have on the annual glacier mass balance. This was not possible before with traditional stake measurements. That avalanche deposits have a significant positive effect on mass balance the glacier surface needs to be small, accordingly we present here data from small glaciers in Svalbard (Austre Lovénbreen; 4.48 km2 in 2013) and Northeast Greenland (Freya Glacier; 5,5 km2 in 2021). The geodetic mass balance of 8 years (2013/14 - 2020/21) of the Frey Glacier is even slightly positive. A main imprint of the near decadal mass balance stems from the exceptional (2.5 standard deviations above average) winter mass balance of 2017/18 with 1.85 + 0.05 m w.e., when in addition to above average precipitation, snow avalanches affected more than one third of the glacier surface and contributed at least 0.31 m w.e. (17%) to the total winter mass balance of 2017/18. We estimate the contribution of avalanches to the accumulated mass balance 2013/14 - 2020/21 as 0.55 m w.e. Without those avalanche events the 8-year mass balance would have been slightly negative, -0.30 m w.e. instead of positive 0.25 m w.e.. Even though the annual mass balance of Austre Lovénbreen is negative since 2013/14, we show that avalanche deposits are the only remaining mass on the glacier surface that contributes positive in some years. However, avalanche deposits were not able to stop glaciers from melting due to climate warming as seen clearly in the data since 2020 also for the Freya Glacier.
Object ID: ISSW2024_P5.8.pdf
Language of Article: English
Presenter(s): Alexander Prokop
Keywords: avalanche deposit, climate warming, arctic glacier, LiDAR, SfM-photogrammetry
Page Number(s): 672 - 676
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