Such snow does not stick in spring, provided it has been through the usual process of melting and refreezing on previous days. But though the spring Föhn does not produce stickiness, it gives the snow a dragging, clogging grip. It may not ‘ball’ under the ski like sticky snow in winter, but on all but steep slopes it makes ski-ing desperately slow. Uphill work is most trying, for the friction between wet Föhn snow and the ski is very marked. The ski have to be thrust through the clinging surface, and the wet Föhn not only affects the snow, it affects one’s whole body and produces a general sense of lassitude.
Summer Snow
Between July and the end of September the snowline climbs ever higher. The snow above this snowline obeys the laws that we have tried to explain in the preceding pages. Snow is transformed into crust by the action of sun or thaw or wind, and the crust itself affords good or bad ski-ing, according to the conditions under which it has been produced and the conditions that affect it when once it has been formed.
In the summer you will meet with every type of snow in the High Alps. After a fresh snowfall the snow will often remain powdery for days on northern slopes at great altitudes. Between July and the beginning of the winter you will find typical winter snow, powder snow or wind-driven snow: you will find typical spring snow, such as film crust or perforated crust, but you will not find any type of snow which can fairly be described as mainly characteristic of the summer. The conditions in July and the first half of August will approximate to those of June, though of course there will be far less snow in August than in June. Towards the end of September the snow conditions will approximate to those of the winter proper, with the important difference that the snow at the end of September approaches a minimum.
Once the ski are left behind and the final climb begun on foot, there will be many complex and difficult problems of snow craft to solve which, however, hardly come within the scope of pure ski-ing. Of these the most important is the problem of safety. Once the ski are left behind, the climber’s interest in the snow is reduced to two main problems: Is the snow hard enough to make going easy and yet not so hard as to need step-cutting? Is the snow safe or will it avalanche?
The avalanche question will be treated in its proper place. Summer Ski-ing will be dealt with on pp. [468-470].
I have tried to condense this section, and, like all condensed and theoretic writing, it will no doubt prove rather dull reading. In the later sections I shall try to provide concrete illustrations of the principles here explained, and to show how the laws of snow craft may be applied in order to get good ski-ing in the months of the alpine calendar.
Snow Avalanches
Snow avalanches may be classified either as Ground avalanches or as Superficial avalanches.
Ground Avalanches—the ‘Grundlawinen’ of Continental writers—may be defined as avalanches in which the entire snow surface is stripped off a slope, revealing the underlying earth, grass or rock.