GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



15 



TABLE II. 



Inversions of Temperature, between the Banff and Sulphur 



Mountain Stations. 



Data supplied by the Canadian Meteorological Service. 

 (Elevation Banff Station, 4,542 feet; Sulphur Mt., 7,4S9 feet.) 



Geologicall}^ the chinooks must exert an infliience, the accumulated effect of 

 which may be considerable. They remove much snow from the eastern slopes 

 of the mountains, which might otherwise be available for glacier formation, 

 raising the lower limit of the snow-line and rendering it tnore irregular. That 

 portion of the melted snow which is not evaporated will course down the moun- 

 tain slopes as water, accomplishing a different work than if it had remained 

 solid. The alternate periods of thawing and freezing during the winter and 

 spring will accelerate the disintegration of rock upon the eastern slopes of the 

 ranges. By this means glaciers lying to the east of, the mountain crests will 

 receive a heavier load of rock debris from neighboring cliffs, talus deposits will 

 be larger than otherwise, and soil fonnation go on at a more rapid rate. At 

 Innsbruck, in the Alps, where the foehn winds blow upon an average 42.6 

 days in the year, the mean annual temperature is raised 1.08° F., or the equiva- 

 lent effect of one degree of latitude. 



• c. Oscillations in climate. The problem of precipitation has been discussed 

 thus far with reference to its geographic distribution over the region, and although 

 a full discussion cannot be here introduced, there still remains the question of 

 its distribution in time. Here again our data are far too scant for satisfactory 

 generalization, but, so far as the evidence goes, it is in harmony with the theory 

 that precipitation occurs in cycles, there being a series, of years in which the total 



