GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 21 



blowing, or in the lee of Lefroy with an east wind. Thus because of its shape, 

 position, and depth the upper valley is able to capture much more snow than it 

 would ordinarily be entitled to. 



c. Upon the opposing faces of Victoria (elevation 11,355 f eet ) an d Lefroy 

 (11,220 feet) large beds of snow accumulate during the fall, winter, and early 

 spring. During the late spring and early summer much of this snow is pre- 

 cipitated into the valley as avalanches, with the roar of thunder and the blast 

 of a tornado. It is the danger from this source that has suggested the name 

 " Death -Trap, " for the narrower portion of the valley, although no fatalities 

 have yet occurred here. These avalanches may shoot directly across the 

 valley, or they may turn and move along it lengthwise as shown in plate vi, 

 figure i . They must bring down numerous rock fragments, which are distributed 

 completely across this portion of the glacier and incorporated into its ne"ve". 



d. A considerable portion of the snow which clings to the eastern shoulder 

 of Mt. Victoria is compacted into stratified ice, and over an area of about one 

 square mile there arises a true glacier perched up on the mountainside, with a 

 slope that appears too steep to give it a foothold. Such a glacier is known 

 as a "cliff glacier," or "hanging glacier" (plate vi, figure 2). It moves down 

 the slope, probably with considerable velocity, and is avalanched into the 

 valley upon the back of the Victoria Glacier, filling the air with ice dust. At 

 the crest of the precipice the ice has an estimated thickness of 200 to 300 feet, 

 from which great blocks, sometimes as large as a city square of buildings, are 

 detached and fall vertically 1,200 to 1,500 feet. At certain places where the 

 falls are more frequent there are built up debris cones of coarse granules upon 

 the western margin of the glacier. This avalanched ice spreads over the glacier 

 and is incorporated into its body along with more or less ground-morainic material 

 which has been manufactured between the hanging glacier and its bed. When 

 the weather is cool and cloudy these ice avalanches are infrequent, but upon 

 a warm bright day, with much melting and more rapid forward movement of 

 the ice, they occur every few minutes from some portion of the long front. On 

 August 25, 1903, during the mid-portion of the day avalanches were noted as 

 follows: 



10:39 A - M - moderate. 12:29 P.M. moderate. 



10:43 slight. 12:49 moderate. 



11:05 slight. 12:52 slight. 



11:27 slight. 1:11 moderate. 



11:28 heavy. 1:18 moderate to heavy. 



11:40 slight. 1:35 moderate. 



12:20 P.M. slight. 



12:27 moderate. 1:52 moderate. 



2:10 moderate. 



Owing to its western and southern exposure the opposite face of Lefroy 

 does not support a hanging glacier, although there is a suitable collecting area 



