But even when unsupported by wind or obscurity, a slight depression or a light cloud may make way-finding difficult on even snow, where there are no rock outlines to penetrate its guile. A diaphanous mist, approaching in tint that of the snow surface, is sufficient to conceal or completely alter distances and angles.
In cases where the mist exactly combines in tone with the snow, a curious phenomenon makes itself uncomfortably evident. The leader on a snowy crevassed glacier will suddenly, and apparently wilfully, begin to fall into crevasses which are visible to those following behind him on the rope. They will marvel at his stupidity, until they begin to lead themselves, when they will reproduce it. The reason will have been that whereas those behind have some dark object, man or rope, upon which to focus their eyes, the eyes of the man in front, looking only upon a uniform blank surface, go out of focus, and become unable to distinguish between details of the same tone. Any detail darker by contrast—a rock, or the length of the rope ahead, or even the sight of a distant peak,—for such mists are often transparent—will yield them a focal point again. If he has no such natural assistance, the leader must keep looking methodically at his feet, and then forward. This will discover to him the nearer crevasses. For a longer view he may try the device of balling snow, till it crushes to a darker colour, and throwing it ahead: he will then again be able to see more distant details in their relation to the passage of the snowball.
In a mist or at night, on glaciers, or on snow slopes where there is reason to suspect the neighbourhood of rocks, it is possible to keep direction, and to discover towards which side of a slope or glacier our march is tending, by shouting, and calculating our position by the time it takes for the echo to return from the rock on either side. Across smooth slopes a very small and remote obstruction will give echo to our appeal.
On open snow slopes where there are no retaining walls, the best method is to have the full length of the rope out, and put a man with the compass at the rear end to correct the leader’s line. If a compass is lacking—if it can ever be lacking in the mountains!—the man far behind is still in the better position to judge, by the pointer of the rope, whether the line is being maintained or is inclining either way.
If a return in mist over the same ground is expected, the tracks should be made intentionally deep, in order to reinforce the line against the sun’s action, which may be all the more rapid when the light is diffused through such mist. The axe should be driven deeply into the snow at short intervals, so as to leave marks which may last longer than footprints; and this especially on hard snow.
On rocks or snow in mist, and even with less excuse on clear days, some other-land climbers adopt the device of marking the line of return at important points of divergence by squares of red paper fixed under stones. In emergency these can be of service; but they are unsightly, and their frequent use encourages climbers to pay insufficient attention to a very important part of their work—which is to note and record in memory the details of a route against the time of their return. A climber who has to find the return line on difficult rock or glacier, or on any climb that winds by devious ways, should never omit at all points of divergence or of salient indication to turn round and note how the passage or kink looks from the opposite direction; which is generally very different from its aspect on the approach. Distant views are often confused and absurdly distorted by mist; but details close at hand, for whose memorizing alone red paper could be a substitute, are seldom sufficiently obscured not to be recognizable by a trained observation and memory. Only in two cases—one, the rare event of an expedition over fog-bound snow being continued with the intention of return over the same line; and two, equally singular, the case of a party, which contains only one mountaineer capable of leading the return route, attempting in mist a climb whose difficulty will necessitate the expert going last on the descent—would the use of red paper seem to be justified. Waste paper is inelegant, and makes an unimpressive substitute for hill craft. But mist is a subtle enemy on glaciers, and we may sympathize with folk who meet it by tricks when they happen to have brought a box of them with them.
The Sense of Direction.
In the end, and behind all memory and observation, we have to fall back upon that useful but mysterious faculty, the sense of direction. Its existence is often denied, especially by men who do not possess it, and its workings are attributed to powers of observation, to unconscious memorizing and to reasoning. But no one who has mountaineered or travelled much in uncharted ground with men of very divergent or very similar powers of sight or experience will be found to discredit its positive but entirely accidental possession. Irrespective of sight and independently of the presence of any other respectable mental faculties, some men are found to possess it and some not; and no experience or study will ever equalize the capacity of those who cannot with that of those who can exercise it in dealing with misty conditions or unknown country. Men who have it only in a slight degree frequently impair its fidelity by training their observation and memory. By taking thought we can nearly always confuse it, in ourselves or in our neighbour; and this fact has especially to be borne in mind in dealing with less educated brains, such as those of guides, where its working is unconscious when it exists at all. A pertinent question or reminder may often set them, or ourselves, thinking or doubting, and lead to hesitation or wandering where a moment before confident movement reigned.
If we have once made certain that a guide or even a younger or less experienced climber possesses it, we may accept its leading thankfully in moments of doubt, although its counsel may contradict our own reasoning or conscientious observation.
Those who do not possess the instinct, and those who possess it only in a small degree, will find it almost impossible in thick mist on featureless snow to avoid the inclination to turn in a circle, generally to the left. In mist, with the most resolute intentions, it is at times even difficult to correct the inclination, by allowing for the stronger thrust of the right foot (or whichever may be the leading foot in our own case) and by taking the axe in the opposite hand to that foot; or by discovering and allowing for our exact amount of bias. The compass is the only secure guide for the ungifted.