AVALANCHES AND GLACIERS
The avalanche is chiefly associated in the mind of the visitor to Switzerland with thoughts of peril and destruction, the glacier with the idea of a permanent field of ice set decoratively to adorn a mountain-side. Neither impression represents all of the truth. Avalanches are destructive, and glaciers decorative. But the avalanche is normally, to the dweller in the Alps, the welcome harbinger of spring; the glacier the hard-working labourer which brings down soil from the mountain rocks for the enrichment of the plains.
The first avalanche is the sign to the Swiss that
Solvitur acris hiems,
and though he will not "draw his fishing boats down by rollers to the sea," in all other respects he will share the song of joy in which Horace records for the Italian husbandman the welcome due to the spring. The avalanche may be sometimes terrible in its destruction, as in lower lands a flood may sometimes be; but on their record, year by year, they do not cause any appalling loss of life or of property. Some deaths, some destruction, can be set to their account, but Nature exacts a penalty from man everywhere, on plain, on mountain, and on sea. Inundations of plains, storms at sea, cause probably a much greater proportionate loss of life and property than avalanches.
In Switzerland, spring is the great time for avalanches. They fall all the year round, chiefly from high levels, but it is in the spring that the greatest avalanches come adrift. Certain spring avalanches descend with remarkable regularity in particular places, one every year. An avalanche falls at a recognised spot in the neighbourhood of almost every village, which dates from its advent the opening of the spring. This spring avalanche is no sudden freak of Nature, but an inevitable affair, slowly engendered. The snow that piles up during the winter months, on what in summer are the grass slopes below the snow-line, gradually becomes unstable as spring melting advances. The mass loses its cohesion, ceases to bind firmly together, and tends to flow downwards. The trend of the ground decides the way of its fall. If the fields upon which it lies are of small area and slope conveniently, the avalanche will slide gently down to its appointed place. But if the disposition of the ground is such that a great mass of snow is collected in a basin which has a narrow outlet, from this a great avalanche will rush like a cataract down the mountain-side until it reaches a barrier sufficiently strong to put a stop to its current.
It is this type of avalanche which is the most likely to do great mischief; but even this pours down rather than falls down the hill slope. Sir Martin Conway recalls his observations of avalanches in their actual progress along the Simplon Road one spring:
Near Berisal I crossed one which had recently come to rest, traversing the road. By its rugged white surface, broken into great protuberances, its solidity, and its general form, it resembled a small glacier. To climb on to it one had to cut steps, so steep were the sides. Higher up I crossed several more such fallen masses, through which gangs of workmen were cutting out the road. Towards the top of the pass the snow was tumbling in smaller masses. Over a hundred little avalanches crossed the road within a couple of hours. Then they stopped. On the Italian side similar conditions obtained, but it was not till I reached Isella that the greatest fall took place, or rather was taking place, for it had begun before I arrived, and it continued after I had passed. There, a narrow gorge, with vertical cliff-sides facing one another, debouches on the main valley. It leads upwards to a great cirque in the hills, a cirque that is a grass-covered alpine pasture in the summer. The avalanche was pouring out through this gorge and piling itself up upon the main valley-floor. How the mass of it was being renewed from behind I could not see. Doubtless all the hillsides above were shedding their snow, and it was flowing down and crowding into and through the gorge with a continuous flow. As the pressure was relieved below by the outpouring of the avalanche on to the valley floor, more snow came down—snow mixed with slush, and semi-liquid under the great pressure that must have been developed....
It is not easy to suggest to the reader the grandeur of effect that was produced. The volume of noise was terrific—a noise more massive and continuous than thunder, and no less deep toned.... The avalanche, pouring through the massive gateway of the hills and polishing its sides, came forth with an aspect of weight and resistless force that was extraordinarily impressive. Yet Nature did not seem to be acting violently, though her might was plain to see. She appeared to act with deliberation: one looked for an end of the snow-stream to come, but it flowed on and on, pulsating but not failing. The pressures that must be developed were easily conceived; correspondingly evident became the strength of the hills that could sustain them as if they had been but the stroking of a hand.
Later in the season the traveller often encounters, in deep-lying valleys, the black and shrunken remnants of these mighty avalanches, melted down by summer heats. Little idea can they give him of the splendour of their birth and the white curdled beauty of their surface when they first come to rest. In the nature of things they travel far and fall low, well into the tree-belt, and even down to the chestnut-level on the Italian side. It is a strange sight to see these vast, new-fallen masses lying in their accustomed beds, but surrounded by trees all freshly verdant with the gifts of spring. Yearly each one falls in the same place, falls harmlessly and duly expected. Its coming is welcomed. Its voice is the triumphant shout of the coming season of summer exuberance and fertility. Nature, newly awakened, cries aloud with a great and solemnly joyous cry, and the people dwelling around hear her and arise to their work upon the land.
The avalanche, then, is one of the great natural forces of the mountains, which is not necessarily or even ordinarily destructive. But, like other natural forces—the fresh in the river or the gale at sea,—it can be very terrible, and, again like other natural forces, the wisdom and precaution of man can do much to minimise the danger of the avalanche and to avert any serious destruction by its agency. The Swiss people, so practical, so economical, so courageous, carry on a persistent scientific campaign against the unruly element in these torrents of ice, setting up lines of defence everywhere. The first and most important line of defence is the forest; and for this reason the forest laws of Switzerland are very severe. A man is not allowed to fell a tree in his own wood without the forester's consent. Everything is done to preserve the natural rampart afforded by a mass of pines. In the second place, where avalanches descend regularly every year, stone galleries are built, or tunnels are mined out of the solid rock to protect roads. There are many examples of these galleries and tunnels in the Züge, near Davos.
Scientific engineers are eager to add to these plans of defence. They believe that the root of the mischief ought to be attacked. In places where avalanches are expected, they recommend the building of terraces and dwarf-walls, so as to arrest the earliest snow-slip. Lower down, in the forest zone, piles should be driven into the ground, and fenced with wattling. These precautions, and others on similar lines, are now being taken, and most of the well-known avalanche tracks are being surrounded by various defensive works designed to arrest any tendency to mischief that they show. Destruction from avalanches there will continue to be in exceptional cases, for Nature insists, now and again, on displaying some unwonted, abnormal display of her power which sets at nought all precautions of man. A Titanic goes to the bottom of the sea to show that the shipbuilder can claim only a human and therefore limited surety against disaster. An avalanche may one day shock Europe by rushing unexpectedly down to overwhelm a whole Swiss village. But the danger from them has been diminished largely, and continues to be diminished. It is necessary to go back to the past to obtain the record of any great number of avalanche disasters.