MOUNTAINEERING, the art of moving about safely in mountain regions avoiding the dangers incidental to them and attaining high points difficult of access. The basis of it is dis covery, and in its methods it bears a strong likeness to navi gation, demanding many of the same qualities, such as foresight, endurance and ceaseless vigilance. It often resembles arctic exploration and, as its scale increases, partakes more and more of the character of a military expedition. It forms two main divisions, rockcraft and snowcraft. Rockcraft consists in the intelligent choice of a line of route and in activity and gymnastic skill to follow the line chosen. In snowcraft the choice of route is the result of a full understanding of the behaviour of snow under a multitude of varying conditions; it depends largely upon experience and much less upon agility. The dangers, to avoid which the craft of climbing has been developed, are of two main kinds ; the danger of things falling on the traveller and the danger of his falling himself. The things that may fall on him are rocks, ice or snow, and he may fall from any one of them or into crevasses in ice. There are also dangers from weather. Thus in all there are eight chief dangers.
Every rock mountain is falling to pieces, the process being specially rapid above the snowline. Rock faces are constantly swept by falling stones which it is generally possible to dodge. Falling rocks tend to form deep and wide channels (coulozrs) in a mountain face and these channels have to be ascended with caution, their sides being often safe while the middle is stone-swept. Stones fall more frequently on some days than on others according to the recent weather. Local experience is a valuable help on such occasions. The direction of the dip of rock strata often determines whether a particular face is safe or dangerous. The character of the rock must also be considered. Where stones fall frequently debris will be found below, whilst on snow-slopes falling stones cut furrows which are visible from a great distance. In planning an ascent of a new peak such traces
must be looked for. When falling stones get mixed in consider able quantity with slushy snow or water, a mud avalanche is formed (common in the Himalaya). It is necessary to avoid camping in its possible line of fall.
The places where ice may fall can always be determined beforehand. It falls in the broken parts (seracs) of a glacier and from overhanging cornices formed along the crests of narrow ridges. Large icicles are found on steep rock faces, and these fall frequently in fine weather following cold and stormy days. They have to be avoided like falling stones. Seracs are slow in formation and slow in arriving (by glacier motion) at a condition of unstable equilibrium. They generally fall in or just after the hottest part of the day and their debris seldom goes far. A skilful and experienced ice-man will usually devise a safe route through the most intricate ice-fall, but such places should be avoided in the afternoon of a hot day. Hanging glaciers (i.e., those perched on steep slopes), often discharge themselves over steep rock faces, the snout breaking off at intervals. They can always be detected by their debris below. Their track should be avoided.
These mainly occur on steep slopes when the snow is in bad condition, early in the year, or after a fresh fall. Days when snow is in that state are easily recognized and then it may be inadvisable to traverse snow-slopes which at other times may be as safe as a high road. Beds of snow collected on rock ledges in bad weather fall off when a thaw comes and are dangerous to rock-climbers. Snow which has recently fallen upon ice-slopes is always liable to slip off bodily. Such falling masses generally make the lower part of their descent by couloirs. Snow avalanches never fall in unexpected places, but have their easily recognizable routes, which can be avoided in times of danger by experienced mountaineers.