Upslope migration of snow avalanches in a warming climate

Abstract

Snow is highly sensitive to atmospheric warming. However, because of the lack of sufficiently long snow avalanche time series and statistical techniques capable of accounting for the numerous biases inherent to sparse and incomplete avalanche records, the evolution of process activity in a warming climate remains little known. Filling this gap requires innovative approaches that put avalanche activity into a long-term context. Here, we combine extensive historical records and Bayesian techniques to construct a 240-y chronicle of snow avalanching in the Vosges Mountains (France). We show evidence that the transition from the late Little Ice Age to the early twentieth century (i.e., 1850 to 1920 CE) was not only characterized by local winter warming in the order of +1.35 °C but that this warming also resulted in a more than sevenfold reduction in yearly avalanche numbers, a severe shrinkage of avalanche size, and shorter avalanche seasons as well as in a reduction of the extent of avalanche-prone terrain. Using a substantial corpus of snow and climate proxy sources, we explain this abrupt shift with increasingly scarcer snow conditions with the low-to-medium elevations of the Vosges Mountains (600 to 1,200 m above sea level [a.s.l.]). As a result, avalanches migrated upslope, with only a relict activity persisting at the highest elevations (release areas >1,200 m a.s.l.). This abrupt, unambiguous response of snow avalanche activity to warming provides valuable information to anticipate likely changes in avalanche behavior in higher mountain environments under ongoing and future warming.

Impacts of Climate Change on Snow Avalanche Activity Along a Transportation Corridor in the Tianshan Mountains

“…When the regional temperature increases by 1 °C, the active time for wet snow avalanches advances by approximately 8 days. Increasing winter air temperatures drove the advance and prevalence of wet avalanche activity in the Tianshan Mountains, given its continental snow climate, similar to previous findings reported in snow climate regions worldwide (Ballesteros-Cánovas et al 2018;Giacona et al 2021;Strapazzon et al 2021). Therefore, it is urgent to adjust the risk prevention and control time for wet snow avalanches and rationally arrange wet snow avalanche relief resources to improve the regional risk management of wet snow avalanche disasters.…”

“…Existing studies have also reported that the behavior of snow avalanches has changed. There are significant regional differences in marine and transitional snow climates (Ballesteros-Cánovas et al 2018;Gratton et al 2020;Giacona et al 2021). The temperature increase rate in the Tianshan Mountains with a typical continental snow climate was 0.34 °C/10 years from 1960 to 2017, significantly higher than the global average temperature increase rate (Li et al 2020).…”

“…The frequency and hazards of snow avalanches at mid-high altitudes have increased with climate warming in the western Himalayas as well (Ballesteros-Cánovas et al 2018). The period of snow avalanche activity has shortened at lower altitudes, and the snow avalanche hazards have increased at higher elevations in the French Alps (Giacona et al 2021). In addition, because higher snow densities in wet avalanche debris are likely to interfere with the respiration of buried victims, asphyxia and trauma as causes of snow avalanche death have increased with climate warming (Strapazzon et al 2021).…”

Geomorphic process chains in high-mountain regions - A review and classification approach for natural hazards assessment

“…The number and area of glacier lakes has increased in most mountain regions of the globe (Shugar et al, 2020), and changes in the decadal occurrences of GLOFs has oscillated (Harrison et al, 2018), but it remains uncertain whether the frequency of GLOFs has increased over the longer term as is widely supposed (Harrison et al, 2018;Veh et al, 2022;Veh et al, 2019). Snow avalanches involving wet snow have increased in several regions and mostly at higher elevations (Ballesteros-Cánovas et al, 2018;Stoffel and Corona, 2018), whereas snow avalanches have become much less frequent at lower altitudes (Castebrunet et al, 2014;Giacona et al, 2021). As a consequence of increases in temperature and snowfall limits, rain-on-snow floods have increased in winter, but have started to decrease in spring (Freudiger et al, 2014).…”

Limited impacts of global warming on rockfall activity at low elevations: Insights from two calcareous cliffs from the French Prealps

“…In mountainous environments, mass movements are particularly sensitive to global warming (Gariano and Guzzetti, 2016; Stoffel and Corona, 2014). As air temperatures continue to rise, mass movements are expected to change in terms of their frequency or magnitude as well as in area affected (Hock et al, 2019; Giacona et al, 2021). Among these mass movements, rockfall is a major driver of landscape evolution on steep mountain flanks (Korup, 2006) and thus also presents a serious hazard in mountain regions across the globe (Bovis et al, 1985; Evans and Degraff, 2002).…”