EGU2020-464
https://doi.org/10.5194/egusphere-egu2020-464
EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Non-stationarity of extreme ground snow load in the French Alps

Erwan Le Roux1, Guillaume Evin1, Nicolas Eckert1, Juliette Blanchet2, and Samuel Morin3
Erwan Le Roux et al.
  • 1Univ. Grenoble Alpes, INRAE, UR ETNA
  • 2Univ. Grenoble Alpes, Grenoble INP, CNRS, IRD, IGE
  • 3Univ. Grenoble Alpes, Univ. Toulouse, Météo France, CNRS, CNRM, CEN Grenoble

In a context of climate change, assessing trends in hazards related to extreme events is urgent. Specifically current methods to compute European standards for snow load actions on structures do not account for the non-stationarity due to climate change. We present the first analysis of extreme ground snow load trends for the whole French Alps. Our method is based on non-stationary generalized extreme value (GEV) distribution, time derivative of return level and likelihood ratio test. Thanks to Météo France reanalysis and snowpack models, we study moutain massif scale data available every 300m of altitude from 1958 to 2017. We detect an overall decreasing trend for annual maxima of ground snow load between 900m and 2700m, which is significant in the Northwest of the French Alps until 1800m. Despite decreasing return levels, in 2017 half of massifs at altitude 1800m still exceeds standard return levels. We underline the importance of snowpack modelling and limitations of approaches relying on ground snow load computed with snow depth annual maxima and an hypothesis on snow density.

How to cite: Le Roux, E., Evin, G., Eckert, N., Blanchet, J., and Morin, S.: Non-stationarity of extreme ground snow load in the French Alps, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-464, https://doi.org/10.5194/egusphere-egu2020-464, 2020.

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