Abstract

Numerous large-scale atmosphere-ocean oscillations including El Nino-Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO), the Pacific North American Pattern (PNA) and the Artic Oscillation (AO) are known to substantially affect winter weather patterns in western Canada. Several studies have examined the effect of these oscillations on avalanche hazard using long-term avalanche activity records from highway avalanche safety programs. While these studies offer valuable insights, they do not offer a comprehensive perspective on the influence of these oscillations because the underlying data only represent the conditions at a few locations in western Canada where avalanches are tightly managed.

We present a new approach for gaining insight into the relationship between atmosphere-ocean oscillations and avalanche hazard in western Canada that uses information published in public avalanche bulletins. Our approach converts hazard assessments recorded according to the conceptual model of avalanche hazard into an avalanche winter characterization following Shandro and Haegeli (2018) and uses mixed effects models to identify response patterns in the prevalence of typical avalanche hazard situations. Even though our study period is short, the large-scale patterns emerging from our analysis agree reasonably well with the known impacts of the oscillations on winter weather in western Canada. However, we also find numerous smaller scale patterns that indicate that the effects on avalanche hazard are more complicated and regionally variable.

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