Meteorological triggering scenarios of tree-ring-based snow avalanche occurrence on scree slopes in a maritime climate, Eastern Canada

ABSTRACT

Statistical relationships between weather conditions and the release of snow avalanches in the low-elevation coastal valleys of the northern Gaspé Peninsula are still poorly validated. As such, we explored climate–avalanche relationships through classification tree algorithms applied to tree-ring reconstructions of avalanche events. In order to assess the contribution of local factors on avalanche activity, avalanche regimes on east- and west-facing slopes were analyzed and compared. The results showed that avalanches on east-facing slopes appear to be primarily related to large cumulative snowfall in January, February, and March. On west-facing slopes, avalanches are mainly due to episodic snowfall and warming temperatures. However, both sides of the valleys showed the potential for the release of large avalanches in November and December, which is earlier than expected by the literature. Indeed, the weather variability at that time of the year (temperature oscillation around 0ºC) appears to favor the formation of an early, unstable snowpack and subsequent triggering of avalanches, such as the wet slab avalanche recorded by a time-lapse camera in November 2014. This camera provided a useful insight on the capacities of classification-tree models to link the yearly resolution of tree-ring data with weather triggers at different timescales.

KEYWORDS:

• Snow avalanche
• tree ring
• dendrogeomorphology
• classification tree
• Gaspé peninsula

Acknowledgments

We would like to thank Jean-Philippe Martin, Stéphanie Morin, and Annie Lagadec for their helpful comments throughout the study and Jean-François Milot for his assistance on the field. We also thank the Associate Editor Charles Lafon and two anonymous reviewers for their helpful comments and suggestions that improved the earlier version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Natural Sciences and Engineering Research Council of Canada [1079284].