While one gazes entranced at the array of lakes and valleys, of snowfields and dark cliffs, the wind rises and mountains to the west put on a cap of cloud. This grows and darkens and presently a mantle of mist sweeps up with the wind, the sun is dimmed and in a few minutes the wide world is shut out by a blizzard. We must make our way down to lower levels where sleet whitens the closing flowers, and then through a belt of rain swept hillside into the valley where the sun may still be shining hotly.
Since snow falls every month in the year on the névé fields and never melts away one might expect the mountains, especially the Selkirks, to grow as snowheaps into the sky; but of course this does not take place. Under the increasing load of snow the lower beds are compressed into ice; so that the névé, beginning as loose or hard drifted snow above passes downwards into ice banded with blue and white layers, the whole sometimes hundreds of feet in thickness.
The snow accumulates only on the gentler slopes or in the higher valleys. On cliffs it cannot lodge but piles upon the névé beneath; and on steep slopes it may lie for a time but now and then, especially toward spring, it breaks loose and thunders down into the valley as an avalanche.
The Motion of Glaciers.
The final disposal of the snowfield, turned to ice in its lower parts, comes by a slow creep downwards. That the névé is actually in motion can be seen by following the slope of snow to its upper edge against some mountain wall where a “BERGSCHRUND” generally yawns between the snowfield and the cliff. This may be several feet wide, and may go down many feet to obscure depths. No amount of snow fall can fill the chasm permanently, though it may be bridged with fresh snow for a time, making a risky passage for the climber.
CAVERN ON ILLECILLEWAET GLACIER
SNOUT OR FOREFOOT OF ROBSON GLACIER, JASPER PARK
The névé is always pulling away from the rocks at its upper border, and its general motion follows the direction of the lowest depression beneath, finally extending below snowline as a tongue of ice which reaches down into the valley until it is melted by the increasing warmth of the lower levels. Thus a glacier is born. Unless whitened by recent storms the glacier is bare of snow in summer with a rough uneven surface of a dirty blue green color, partly covered with rocky debris, and its volume diminishes downward by thawing until at a definite point the whole is melted and flows away as a river of water instead of ice. The lower end is sometimes called the “tongue” or “snout” or “foot” of the glacier—a bad case of mixed metaphors.