Climate drivers of large magnitude snow avalanche years in the U.S. northern Rocky Mountains

Abstract

Large magnitude snow avalanches pose a hazard to humans and infrastructure worldwide. Analyzing the spatiotemporal behavior of avalanches and the contributory climate factors is important for understanding historical variability in climate-avalanche relationships as well as improving avalanche forecasting. We used established dendrochronological methods to develop a long-term (1867–2019) regional avalanche chronology for the Rocky Mountains of northwest Montana using tree-rings from 647 trees exhibiting 2134 avalanche-related growth disturbances. We then used principal component analysis and a generalized linear autoregressive moving average model to examine avalanche-climate relationships. Historically, large magnitude regional avalanche years were characterized by stormy winters with positive snowpack anomalies, with avalanche years over recent decades increasingly influenced by warmer temperatures and a shallow snowpack. The amount of snowpack across the region, represented by the first principal component, is shown to be directly related to avalanche probability. Coincident with warming and regional snowpack reductions, a decline of ~ 14% (~ 2% per decade) in overall large magnitude avalanche probability is apparent through the period 1950–2017. As continued climate warming drives further regional snowpack reductions in the study region our results suggest a decreased probability of regional large magnitude avalanche frequency associated with winters characterized by large snowpacks and a potential increase in large magnitude events driven by warming temperatures and spring precipitation.

Large-ensemble climate simulations to assess changes in snow stability over northern Japan

“…The potential decrease in avalanche formation over northern Japan (Fig. 6) also agrees with the decreasing trend of avalanche occurrence in the recent decades in the French Alps (Eckert and others, 2013), Swiss Alps (Teich and others, 2012a) and the US Northern Rocky Mountains (Peitzsch and others, 2021) and the estimation based on the combination of a climate model, a physical snowpack model and past avalanche records in the French Alps (Castebrunet and others, 2014). The warmer climate perhaps reduces the avalanche commonly in many countries, including Japan.…”

“…Snow avalanches frequently destroy forests, infrastructures, houses and lives. Recent avalanche records showed a decreasing trend of avalanche occurrence, which was negatively/positively correlated with air temperature/snowfall, from the 1970s in the French Alps (Eckert and others, 2013) and Swiss Alps (Teich and others, 2012a) and from the 1950s in the US Northern Rocky Mountains (Peitzsch and others, 2021), especially in low elevations (Lavigne and others, 2015; Giacona and others, 2021). Similarly, the avalanche magnitude retrieved from runout distance or extent of avalanche-prone terrain has been decreased in recent decades below an elevation of 1200 m in the Vosges Mountains in France (Giacona and others, 2021).…”

Field observations and remote assessment identify climate change, recreation, invasive species, and livestock as top threats to critically imperiled rare plants in Nevada

“…Avalanche activity is a natural process, and species growing in or near avalanche chutes are likely to be adapted to some avalanche activity. However, populations may be vulnerable to habitat destruction due to large avalanches, or to climate changeinduced differences in avalanche size or frequency (Ballesteros-Cańovas et al, 2018;Peitzsch et al, 2021). No state-wide geospatial data depict avalanche threat for Nevada; however, research suggests that avalanches are most common in open areas at mid-to-high elevations and on moderate slopes (Perla, 1976;Schweizer et al, 2003;Guy and Birkeland, 2013).…”

Tree‐Ring Derived Avalanche Frequency and Climate Associations in a High‐Latitude, Maritime Climate

“…Peitzsch, Pederson, et al. (2021) found winters with persistent low pressure, negative anomalies of the PDO and positive snow depth anomalies as a major contributor to years with LMA activity.…”