In winter the buttresses and ridges of a cliff, broadly speaking, are technically harder than the gullies. A comparatively thin layer of snow and ice covers the outstanding rocks, tending to discourage all but the expert, whereas the snow-filled gullies, with the summer pitches wiped out and the lack of exposure, tempt the novice into thinking that here he will enjoy easy and safe climbing. This is a fallacy. It is not coincidence that all the accidents in this chapter, with the possible exception of two, happened in gullies. Certainly the buttresses attract the expert who is less likely to involve himself or his party in trouble, but the main reason for the potential danger of the gullies is the quantity and different quality of the snow, combined with the novice's inexperience of winter climbing.

There is no danger in large quantities of snow if the quality is good. But a great depth is not built up from one fall; in a Scottish winter season there are constant fresh falls. The old layers, through the action of high day temperatures and cold nights, will consolidate into snow-ice. New snow falls on this and will not adhere until it has thawed a little, then frozen to the under layer. The fresh layer, perhaps only a few inches deep, may remain for some considerable time on top of the snow-ice without adhering to it. And until that point is reached the whole slope is highly dangerous: potential avalanche material, and should be left strictly to itself.

However, the top layer may not be so new as this; there may be some adherence, in which case the expert may decide that, with care, the slope will not be dangerous. With care is the operative phrase. Novices cannot decide the point at which snow may be ventured on if treated with caution, nor do they possess the high standard of technique required in dealing with it in this condition. One of the commonest mistakes in climbing snow which is only just adhering to the snow-ice is to skimp the hard work; that is, to cut or kick steps in the top layer only, disregarding the ice or snow-ice underneath. It is like building a house on sand.

The most important factor to snow-climbing is this recognition of the qualities of adherence. The same factor is involved in the behaviour of cornices. When climbers fall of these, or when cornices at the heads of gullies collapse on parties far below, the initial mistake was very likely the inability to recognise unsafe snow.

There are three main causes for the collapse of a cornice. The first is involved when mild air and rain render it so top-heavy that it will fall without human agency. Secondly, and perhaps aided by a thaw, the great overhanging eave of snow will come down under the axe of the inexpert mountaineer, as happened in the Y Garn accident in Chapter One. The third cause is less obvious and has given rise to the fallacy that specified cornices collapse without manual disturbance.

Such a cornice is that at the head of Central Gully on Great End in the Lake District. In February 1961 ten men were avalanched here, falling between six and eight hundred feet. Surprisingly, none was filled. An intense thaw had set in about 8.0 am on the morning of the accident and new snow fell during the day.

A year later a party of three were avalanched in the same gully. They fell four or five hundred feet. One man was killed and another seriously injured. Conditions on this day Continue to Page 2