Background
Marty and Blanchet (2012) report that "heavy snowfall and extreme snow depth cause serious loss of human life and property in many middle and high latitude countries almost every winter," noting that "heavy snowfalls are often accompanied by extreme snow storms and avalanches." And now - "to improve our knowledge of natural avalanche variability in the context of climate warming" - Corona et al. write that "sufficiently long data series are needed spanning periods for which conditions were different from today."

What was done
In an effort to provide just such data, and noting that "the use of tree rings for the reconstruction of chronologies of snow avalanching has a decades-long history, with increasing sophistication characterizing most recent applications (Butler and Sawyer, 2008)," Corona et al. developed a 700-year dendrogeomorphic reconstruction of avalanche events for a slope of the Queyras Massif (French Alps) where multi-centennial larch trees (Larix decidua Mill.) were apparently able to survive repeated avalanche activity." This high-resolution tree-ring record was then compared with an existing historic chronology to evaluate its accuracy, after which they say they examined "the coincidence between fluctuations in avalanche frequency and historic climate data including temperature."

What was learned
The six scientists identified 38 destructive snow avalanches that occurred between 1338 and 2010 that reached the hamlet of Echalp during the last seven centuries; but they say that "no significant temporal trend was detected concerning the frequency of these extreme events."

What it means
Even during the transition from the greatest cold of the Little Ice Age to the greatest warmth of the Current Warm Period, there was neither an increase nor a decrease in the frequency with which destructive snow avalanches occurred in the studied region of the French Alps.

References
Butler, D.R. and Sawyer, C.F. 2008. Dendrogeomorphology and high-magnitude snow avalanches: A review and case study. Natural Hazards and Earth System Science 8: 303-309.

Marty, C. and Blanchet, J. 2012. Long-term changes in annual maximum snow depth and snowfall in Switzerland based on extreme value statistics. Climatic Change 111: 705-721.