AVALANCHES. 7 



men and cattle, and sometimes fills up rivers, and stops their course. 

 Besides what is covered with masses of snow, persons are often killed, 

 and houses overthrown, by the sudden compression of the air, caused by 

 the incredible velocity with which these enormous masses descend. 

 There are four different kinds of avalanches ; viz. drift, rolling, sliding, 

 and glacier or ice avalanches; of which the first commonly take place in 

 the early part of winter, the second and third at the end of winter or in 

 spring, and the last only in summer. The drift or loose snow avalanches 

 (the Swiss call them staub lauinen) take place when heavy snow has 

 fallen in the upper region of the mountains during a still calm, and this 

 accumulated mass, before it acquires consistency, is put in motion by a 

 strong wind. The snow is driven from one declivity to another, and so 

 enormously increased in its progress, that it brings down an incredible 

 volume of loose snow, which often covers a great part of a valley. The 

 damage caused by these avalanches is, however, generally not very great, 

 because most of the objects covered by them may be freed from the snow 

 without having sustained great damage; but they often produce such a 

 compression in the air, that houses are overturned, and men and cattle 

 suffocated. 



The rolling avalanches are much more dangerous and destructive. 

 These take place when after a thaw the snow becomes clumsy, and the 

 single grains or flocks stick to one another, so as to unite into large hard 

 pieces, which commonly take the form of balls. Such a ball, moved by 

 its own weight, begins to descend the inclined plane, and all the snow it 

 meets in its course downwards sticks firmly to it. This snow mass, 

 increasing rapidly in its progress, and descending with great velocity, 

 covers, destroys, or carries away, every thing that opposes its course 

 trees, forests, houses, and rocks. This is the most destructive of these 

 avalanches, and causes great loss of life and property. In the year 1749, 

 the whole village of Reuras, in the Canton of the Grisons, was covered, 

 and, at the same time, removed from its site, by an avalanche of this 

 description; but this change, which happened in the night time, was 

 effected without the least noise, so that the inhabitants were not aware of 

 it, and on awaking in the morning could not conceive why it did not 

 grow day. A hundred persons were dug out of the snow, sixty of whom 

 were still alive, the interstices between the snow containing sufficient air 

 to support life. In 1806, an avalanche descended into Val Calanca, 

 likewise in the Canton of the Grisons, transplanted a forest from one 

 side of the valley to the other, and placed a fir tree on the roof of a 

 parsonage house. In 1820, sixty-four persons were killed at Fettan, in 



