They are concave when the slopes converge towards a central dividing line lying deeper, to the eye, than their sides; these are scooped out of the hill.
Concave slopes are:—
1. Funnel-shaped, when the funnel may be either upright or upside down.
If it is upright, the wide opening is at the top. If the slope affect the shape of a reversed funnel, it opens out at the bottom, but it may also be choked up in the middle, opening up again above, like an hour-glass.
Concave slopes are quite safe if strewn with rocks, overgrown with shrubs, or wooded. They are untrustworthy if the sides have been planed down, as it were, by what we may call natural wear and tear.
The reader sees here how the indications of nature may be properly interpreted. It is quite clear that a gorge which is a natural shrubbery, for instance, has not been visited by avalanches for a time at least as long as the plants took to grow to their visible size.
The trouble here is that Londoners, for example, having to deal with a gorge which they have not seen free from snow, cannot be expected to tell whether it is safe or not. The local man alone—a permanent eye-witness—possesses the information required, and failing actual acquaintance with the place, a practised mountaineer alone can form an opinion.
Slopes are convex when the centre line, to the eye, rises above their sides. These stand out from the hill, diverging from its top.
Convex slopes should be ascended and descended along the dividing-line. This line, as a dominating centre, will always be sought out by the good High Alp runner. It is both the shortest and surest path from point to point, and great is the delight to see at one’s feet the avalanche runs. If the coping is occupied by rocks, the runner will keep to the snow near to the rocks, but he has no business there at all if the rock ridge is considerable enough to harbour avalanche snow. A practised eye sees at a glance whether snow in excess of the capacity of the gullies is still suspended above the runner’s head, or whether it lies in cakes and balls at his feet.
Here again the native will know. It would help you but little to say that you have found him out to be an unconventional runner, that he is slow and not at all the handy man you expected. However much you may be entitled to fancy yourself or your skill as a conventional runner, he is the better mountaineer, and should your conventional style leave you in the lurch, he is the fellow to do the right thing for you. It is then just as well to remember, when one writes in a home magazine, that, on the spot, one was the incompetent person of the party. “He of the ice-axe,” your guide, would do that second job, too, far better than you, if the use of the pen in that periodical was not inconsistent with his inferior social standing and extremely imperfect education.