Global distribution of snow avalanches and changing activity in the Northern Hemisphere due to climate change

Abstract

Snow avalanches occur in the mountains of all continents and climatic zones. The lower boundary of avalanche distribution rises from sea level in polar and temperate zones to 6000 m in the tropics. Four altitudinal belts of avalanching are distinguished: (I) permanent snow; (II) stable seasonal snow cover; (III) unstable snow cover; and (IV) rare snowfalls. Most avalanche-danger areas of the world belong to the stable seasonal snow-cover bell. Using data from a GFDL Q-flux Model, we estimated possible changes of the main characteristics of the avalanche regime in the Northern Hemisphere: depth of snow cover, duration of the avalanche-prone period and number of days with avalanche-prone snowfalls. At the beginning of the twenty-first Century, there will likely be a smoothing of the sharp differences in avalanche activity between various mountain regions of the World. Avalanche activity should be less in the most active regions and it is likely to increase in regions with low avalanche activity.