Avalanches are of four kinds

Powdery avalanches consist of snow which has become loose and dry from long frost. They therefore occur generally in winter, and are dangerous mainly by the atmospheric disturbance caused by them. The victims generally die of suffocation. Creeping avalanches are ma es of snow which are loosened by spring, but which are on a gentle slope, and only creep down slowly by the force of their own weight. Glacier avalanches are only ma es of ice which split off in summer with a great noise, and go clattering down a precipice to be smashed to pieces at the bottom. The real avalanches consist of huge accumulations of snow, which are hurled over almost perpendicular walls of rock into the valleys beneath. One which fell in Italy in 1885 was calculated to contain 250,000 tons of snow. The famous avalanche of 1827 swept away half the villages of Biel, with 88 inhabitants.