Except on frequented routes, it is never safe to assume the security of big detached blocks, poised on ridges or choked in gullies, unless their fashion of support is absolutely demonstrable. They should be left to the last man to test. From all accounts rash leaders who neglected this precaution have escaped more often and more miraculously than their intelligence, at least, deserved. A leader, if he has any doubt, should avoid touching such blocks altogether. If, for all his caution, a block gives unaccountably, he must hang on to it for all he knows, until the men below have got what shelter they can. Nor must he forget the rope. If the block catches the rope in falling, the danger is as great as if it strikes one of the party.
Apart from these and other permanent idiosyncrasies, most normally sound rock surface will be found to have its times and places of weathering or weakness. We have to learn to recognize the symptoms, forgetting our prejudices in favour of old and trusted rock types, and treat their intrusion with all the delicacy and consideration of tread and touch which we owe to the small infirmities of tried friends.
In so far as they are, or were, rock, moraine and scree may be called unsound.
Moraine and Scree.
The occasional stone on a steep glacier is a find for a foothold; but the stones that coat the ice-core of moraine slopes are merely treacherous. If we have to traverse a few steps on such a slope, it is best to knock the stone out and tread in its ice-socket.
The summit edges of moraines often offer passable going, especially if previous parties have knocked off the final blocks. Their side walls, whether of stone or of stone and mud conglomerate, are the least scalable and most exasperating inclines in the mountain world. They are often even too hard to make steps in, and it is fatal to attempt short cuts upon them.
In traversing along scree slopes, if the scree is small, the one thing to remember is to ‘accept the slip’; to place the foot lightly and let it slip till it stops; not to make convulsive efforts to recover it, or to keep the foot up to the same line of traverse. If the foot slips too far on steep scree, lean inward on the axe or stick, which is held point inward across the body. To ‘rush’ scree on anything but the downgrade is merely to waste energy and time. In ascending or traversing take short steps; tread always for a particular stone, and do not brown the mass of stones vaguely with a loose foot.
In travelling up or along big scree or moraine, balance and a sustained rhythm are the thing to aim at. On flat-stone moraine, step for the middle of the stone; on round or cornered stones, ‘dance’ from one upper edge to the next. Rather than break the rhythm, if no good hold, or possibly only an insecure-looking block, presents itself for the next foot, slacken the knee and put no weight on the leg while you are using the loose block; skimmer over it with the dropped leg of a horse at a big bank, and trust to the next step to bring you up again. If you balance lightly and move fast, a moving foothold is all but as good as a fixed one.
On moraine the axe is always our third leg of balance. On long moraines, or in traversing up or across scree slopes, it saves labour in the task of choosing stones to follow close behind another man, and let the swing of his feet draw yours mechanically on to the footholds he has used.
To descend light scree is one of the chief rewards of a long climbing day: to descend big scree one of its worst penances. The method falls more properly under the section devoted to Glissading.