When glaciers slide down:
Not all mountain glaciers on Earth flow slowly, with typical speeds of a few meters to hundreds of meters per year. Individual glaciers can become unstable and temporarily move much faster. So-called surging glaciers flow over periods of months to a few years at up to several kilometres per year, and often advance over several kilometres. In another type of glacier instability, ice avalanches, ice breaks off from steep glacier areas and creates avalanches, similar to snow avalanches. A third, though rare type of glacier instability, which was only recently recognized, combines the large volumes of glacier surges with the high speeds of ice avalanches. In these glacier detachments, large parts of flat mountain glaciers, up to 100 million cubic meters and more, suddenly slide off and race down a valley at speeds of up to 300 km / h. Global warming is changing where, how often and how large glacier instabilities can occur in the high mountains and Polar Regions of the world. Changes in ice avalanches, glacier surges, and glacier detachments, however, are associated in a complex way with an increase in air temperatures. Depending on local conditions, the hazards from these processes can increase or decrease.