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| Titel |
Projected changes of snow conditions and avalanche activity in a warming climate: the French Alps over the 2020-2050 and 2070-2100 periods |
| VerfasserIn |
H. Castebrunet, N. Eckert, G. Giraud, Y. Durand, S. Morin |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 5 ; Nr. 8, no. 5 (2014-09-15), S.1673-1697 |
| Datensatznummer |
250116312
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| Publikation (Nr.) |
 copernicus.org/tc-8-1673-2014.pdf |
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| Zusammenfassung |
Projecting changes in snow cover due to climate warming is important for
many societal issues, including the adaptation of avalanche risk mitigation
strategies. Efficient modelling of future snow cover requires high
resolution to properly resolve the topography. Here, we introduce results
obtained through statistical downscaling techniques allowing simulations of
future snowpack conditions including mechanical stability estimates for the
mid and late 21st century in the French Alps under three climate
change scenarios. Refined statistical descriptions of snowpack
characteristics are provided in comparison to a 1960–1990 reference period,
including latitudinal, altitudinal and seasonal gradients. These results are
then used to feed a statistical model relating avalanche activity to snow
and meteorological conditions, so as to produce the first projection on
annual/seasonal timescales of future natural avalanche activity based on past observations. The resulting statistical indicators are
fundamental for the mountain economy in terms of anticipation of changes.
Whereas precipitation is expected to remain quite stationary, temperature increase interacting with topography
will constrain the evolution of snow-related variables on all considered spatio-temporal scales and will, in
particular, lead to a reduction of the dry snowpack and an increase of the wet snowpack.
Overall, compared to the reference period, changes are strong for the
end of the 21st century, but already significant for the mid century.
Changes in winter are less important than in spring, but wet-snow conditions
are projected to appear at high elevations earlier in the season. At the
same altitude, the southern French Alps will not be significantly more
affected than the northern French Alps, which means that the snowpack will
be preserved for longer in the southern massifs which are higher on average.
Regarding avalanche activity, a general decrease in mean (20–30%) and
interannual variability is projected. These changes are relatively strong
compared to changes in snow and meteorological variables. The
decrease is amplified in spring and at low altitude. In contrast, an
increase in avalanche activity is expected in winter at high altitude
because of conditions favourable to wet-snow avalanches earlier in the season.
Comparison with the outputs of the deterministic avalanche hazard model
MEPRA (Modèle Expert d'aide à la Prévision du Risque d'Avalanche) shows generally consistent results but suggests that, even if the
frequency of winters with high avalanche activity is clearly projected to
decrease, the decreasing trend may be less strong and smooth than suggested
by the statistical analysis based on changes in snowpack characteristics and
their links to avalanches observations in the past. This important point for
risk assessment pleads for further work focusing on shorter timescales.
Finally, the small differences between different climate change scenarios
show the robustness of the predicted avalanche activity changes. |
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