2. A Descent in exactly the same Tracks as were used for the Ascent.—This method is based on the presumption that a snow-bridge which held in the morning during the ascent will hold during the descent. Obviously the strain is much less during the fast descent than during the climb. Also, as the variations of temperature in winter are of no great importance, provided that the temperature remains below freezing, a snow-bridge which holds in the morning should hold in the afternoon, though the same cannot, of course, be said in summer. As the tracks of the ascent were presumably made on sealskins, the descent must also be made on sealskins if it be desired to follow with any accuracy the line of the ascent and to avoid rapid swings and turns which are liable to test severely a snow-bridge strong enough to resist the ordinary uphill track. For my part, though this method is sometimes used, I consider that the necessity to wear skins and to keep exactly along one line is just as troublesome and not nearly so safe as the rope.
What usually happens when people start a descent without skins, but with the pious intention of keeping to the uphill tracks, is that they very soon find themselves curving and swinging some considerable distance from their old tracks.
3. A Free Descent Unroped.—If you discard the rope, you should be doubly careful to reduce risk to a minimum by paying attention to the general laws of crevasse formation. The middle of a glacier is usually the safest part of the glacier in winter. Lateral crevasses, i.e. crevasses at the side of the glacier, are wider, more numerous, and more complicated than transverse crevasses. The crevasses in the middle of a glacier are usually at right angles to the line of flow, so that a ski-runner who is running straight will cross them at their narrowest breadth. Lateral crevasses usually run at an angle of 30-45 degrees to the line of flow,[23] so that they will usually be crossed by a ski-runner at a more or less wide angle, and the danger of running along the whole length instead of across a snow-bridge is therefore great.
The principal rules for glacier ski-ing in order of importance are as follows: (1) Don’t fall. (2) Don’t make sudden swings. (3) Run straight. (4) Don’t use your stick. (5) Keep to the middle of the glacier.
In other words, run as straight as you can consistent with not falling. It is better to run straight and to use your stick to reduce your speed than to check your speed by swings and turns, for a swing to a standstill above a crevasse is more likely than any other ski-ing manœuvre to break a snow-bridge.
Keep close together on the descent, but not too close. Above all things, avoid crossing the same snow-bridge while another member of the party is crossing it. In the Grenz glacier accident three members of the party fell into the same crevasse.
Avoid short sharp turns, and cultivate long gentle turns if you cannot run straight.
It is often advisable to follow the leader’s tracks, for if the leader has passed over a crevasse without falling in, the chances are that you will be equally fortunate.
There should be two ropes in the party, so that if one rope disappears with its bearer into a crevasse the second rope may be available to pull him out.
At least one rope, and, in addition, the first-aid case and mending apparatus for ski, should be in the rear of the party, as nothing is more annoying than to see the leader disappearing far below with the spare ski-tip just as your ski-point has snapped off.