551.31 



I. 



The Great Avalanche on the Gemmi Pass. 



THE following is the substance of a report made by Professors 

 Heim, Forel, and Chodat (of Zurich, Lausanne, and Geneva 

 Universities respectively) on the subject of the great avalanche from 

 the Altels Glacier, as the result of a personal and detailed study of 

 the scene of the catastrophe. 



On the snowy brow of the Altels (see the map, Fig. i) is now 

 seen a broad semicircular scar representing an ice-cliff of about 

 150 feet in height, and marking the point where the central glacier 

 parted in twain. The two lateral glaciers ordinarily descend to a 

 much lower level than the central one, which comes direct from the 

 summit of the mountain. These have stood firm, though it is not 

 easy to understand how that on the south side has been able to resist 

 the shock caused by the loosening and headlong descent of the mass 

 of ice abutting on its upper portion. In point of fact, an enormous 

 lateral crevasse, which is visible above the line of separation, gives 

 rise to fears lest the phenomenon should repeat itself. However, the 

 Bernese engineers consider the shock to have been such as must have 

 carried away everything that could possibly be detached. 



According to the professors' observations, two transverse crevasses 

 on opposite sides of the central glacier had lengthened until they at last 

 coalesced. The continuous heat of the summer considerably enlarged 

 the fissure. Thus the glacier became divided into a lower and an 

 upper portion, the latter of which is still in place. On the night of 

 the catastrophe there had been a violent fohn wind constantly blowing. 

 The remaining points of detachnient may thus have been loosened, 

 while the water pouring into the crevasse and continuing its course 

 below the glacier carried on the work of disintegration. It must be 

 remembered that the phenomenon was facilitated by the fact that the 

 strata on which the glacier rests have a remarkably even slope of 45°. 

 The separation of the two parts of the glacier was thus bound to result 

 in the precipitation of the lower portion down the mountain side. It 

 is in the upper part that the slope of the rock-bed is most regular ; 

 lower down there are some slight undulations, while 200 metres above 

 the Spitalmatte, which lies at the foot of the mountain, there is a 

 projecting terrace almost vertically dominating it. It is over the edge 

 of this terrace that the mass of ice was hurled in its bound on to the 



pasturage, clearing in part the ground just at the foot of the rock. 



c 



