Part 4 (1/2)
In snowy zones the avalanche is commonly called a snow-slide, or simply a slide. A slide, with its comet tail of powdered snow, makes an intense impression on all who see one. It appears out of order with the scheme of things; but, as a matter of fact, it is one of gravity's working ways, a demonstration of the laws of sliding bodies. A smooth, steep slope which receives a heavy fall of snow will promptly produce or throw off a sliding ma.s.s of snow. Raise, lower, or roughen this slope, increase or decrease the annual snow-fall, or change the direction of the wind,--and thus the position of snow-drifts,--and there will follow corresponding slide-action. Wind and calm, gravity, friction, adhesion, cohesion, geology, temperature and precipitation, all have a part and place in snow-piling and in slide-starting.
The Century slides are the damaging ones. These occur not only at unexpected times but in unexpected places. The Century slide is the deadly one. It usually comes down a course not before traversed by a slide, and sometimes crashes through a forest or a village. It may be produced by a record-breaking snow or by snow-drifts formed in new places by winds from an unusual quarter; but commonly the ma.s.s is of material slowly acc.u.mulated. This may contain the remnant snows and the wreckage spoils of a hundred years or more. Ten thousand snows have added to its slowly growing pile; tons of rock-dust have been swept into it by the winds; gravel has been deposited in it by water; and gravity has conducted to it the crumbling rocks from above. At last--largely ice--it breaks away. In rus.h.i.+ng down, it gathers material from its predestined way.
In the spring of 1901, one of these slides broke loose and came down the slope of Gray's Peak. For years the snow had acc.u.mulated on a ridge above timber-line. The ma.s.s shot down a steep slope, struck the woods, and swept to the bottom about four thousand feet below, mowing down every tree in a pathway about three hundred feet wide. About one hundred thousand trees were piled in wild, broken wreckage in the gorge below.
Although a snow-slide is almost irresistible, it is not difficult, in many localities, to prevent slides by anchoring the small snow-drift which would slip and start the slide. In the West, a number of slides have been suppressed by setting a few posts in the upper reaches of slopes and gulches. These posts pinned fast the snow that would slip.
The remainder held its own. The Swiss, too, have eliminated many Alpine slides by planting hardy shrubbery in the slippery snowy areas. This anchorage gives the snow a hold until it can compact and freeze fast. Shrubbery thus is preventing the white avalanche!
A slide once took me with it. I was near the bottom of one snowy arm of a V gulch, waiting to watch Gravity, the world-leveler, take his next fragment of filling to the lowlands. Separating these arms was a low, tongue-like rock-ledge. A gigantic snow-cornice and a great snow-field filled, with full-heaped and rounded measure, the uppermost parts of the other arm.
Deep rumblings through the earth, echoings from crags and canons through the communicative air, suddenly heralded the triumphant starting of an enormous slide. About three hundred feet up the heights, a broken end-on embankment of rocks and snow, it came coasting, dusting into view, plunging towards me. As a rock-ledge separated the two ravines above the junction, I felt secure, and I did not realize until too late that I was to coast down on the slide.
Head-on, it rumbled heavily toward me with its mixed and crumbling front, making a most impressive riot of moving matter. Again and again the snowy monster smashed its shoulder into the impregnable farther wall. At last, one hundred feet high and twice as wide, came its impinging, crumbling front. At times the bottom caught and rolled under, leaving the overhanging front to cave and tumble forward with snowy splashes.
This crumbling front was not all snow; occasionally an iceberg or a cargo of stones fell forward. With snow flying from it as from a gale-swept, snow-piled summit, this monster of half a million tons roared and thundered by in a sound-burst and reverberation of incomparable depth and resonance, to plunge into a deeper, steeper rock-walled gorge. It probably was moving thirty-five or forty miles an hour and was gaining in velocity every second.
The noise of its pa.s.sing suppressed the sounds of the slide that started in the gulch above me. Before I could realize it, this slide swept down, and the snow on which I was standing burst up with me into the air, struck and leaped the low ledge, rammed the rear end of the pa.s.sing slide, and landed me, snowshoes down, on top of it.
The top was unstable and dangerous; it lurched, burst up, curled under, yawned, and gave off hissing jets of snow powder; these and the plunging movements kept me desperately active, even with my broad snowshoes, to avoid being swallowed up, or overturned and smothered, or crushed in the chaotic, fissuring ma.s.s.
As its speed increased, I now and then caught a glimpse, through flying, pelting snow-particles, of shooting rocks which burst explosively through the top. At timber-line the gorge walls abruptly ended and the channel curved swiftly to the left in a broad, shallow ravine. The momentum of this monster carried it out of the ravine and straight ahead over a rough, forested ridge.
Trees before it were crushed down, and those alongside were thrown into a wild state of excitement by the violence of swiftly created and entangling gale-currents. From the maelstrom on the top I looked down upon the panic through the snow-dust-filled air and saw trees flinging their arms wildly about, bowing and posturing to the snow.
Occasionally a treetop was snapped off, and these broken tops swirled wildly about, hurried forward or backward, or were floated upward on rotating, slower currents. The sides of the slide crumbled and expanded; so it became lower, flatter, and wider, as it slid forward on a moderate up grade. A half-mile after leaving the gorge, the slide collided at right angles with a high moraine. The stop telescoped the slide, and the shock exploded the rear third and flung it far to right and left, scattering it over a wide area. Half a minute later I clawed out of the snow-pile, almost suffocated, but unhurt.
Toward the close of my last winter as government ”Snow Observer” I made a snowshoe trip along the upper slopes of the Continental Divide and scaled a number of peaks in the Rocky Mountains of central Colorado. During this trip I saw a large and impressive snow-slide at a thrillingly close range. It broke loose and ”ran”--more correctly, plunged--by me down a frightful slope. Everything before it was overwhelmed and swept down. At the bottom of the slope it leaped in fierce confusion from the top of a precipice down into a canon.
For years this snowy ma.s.s had acc.u.mulated upon the heights. It was one of the ”eternal snows” that showed in summer to people far below and far away. A century of winters had contributed snows to its pile. A white hill it was in the upper slope of a gulch, where it clung, pierced and anch.o.r.ed by granite pinnacles. Its icy base, like poured molten lead, had covered and filled all the inequalities of the foundation upon which it rested. Time and its tools, together with its own height and weight, at last combined to release it to the clutch and eternal pull of gravity. The expanding, shearing, breaking force of forming ice, the constant cutting of emery-edged running water, and the undermining thaw of spring sent thundering downward with ten thousand varying echoes a half-million tons of snow, ice, and stones.
Head-on the vast ma.s.s came exploding toward me. Wildly it threw off ma.s.ses of snowy spray and agitated, confused whirlwinds of snow-dust.
I was watching from the top of a precipice. Below, the wide, deep canon was filled with fleecy clouds,--a bay from a sea of clouds beyond. The slide shot straight for the cloud-filled abyss and took with it several hundred broken trees from an alpine grove that it wrecked just above the precipice.
This swift-moving monster disturbed the air, and excited, stampeding, and cyclonic winds flung me headlong, as it tore by with rush and roar. I arose in time to see the entire wreckage deflected a few degrees upward as it shot far out over the cloud-made bay of the ocean. A rioting acre of rock-fragments, broken trees, shattered icebergs, and ma.s.ses of dusting snow hesitated momentarily in the air, then, separating, they fell whirling, hurtling, and scattering, with varying velocities,--rocks, splintered trees, and snow,--in silent flight to plunge into the white bay beneath. No sound was given forth as they fell into, and disappeared beneath, the agitated sea of clouds. How strange this noiseless fall was! A few seconds later, as the wreckage reached the bottom, there came from beneath the silent surface the m.u.f.fled sounds of crash and conflict.
Wild Folk of the Mountain-Summits
Wild Folk of the Mountain-Summits
The higher mountain-ranges rise far above the zone of life and have summits that are deeply overladen with ancient snow and ice, but the upper slopes and summits of the Rocky Mountains of Colorado and the Sierra of California are not barren and lifeless, even though they stand far above the timber-line. There is no other mountain-range on the earth that I know of that can show such a varied and vigorous array of life above the tree-line as do these ranges. In the Alps the upper slopes and summits stand in eternal desolation, without life even in summertime. The icy stratum that overlies the summit Alps is centuries old, and is perpetual down to nine thousand feet.
Timber-line there is only sixty-four hundred feet above sea-level. How different the climatic conditions in the Rocky Mountains and in the Sierra, where timber-line is at approximately eleven thousand five hundred feet, or a vertical mile higher than it is in the Alps!
Even the high peaks of this region have touches of plant-life and are visited by birds and beasts. The list of living things which I have seen on the summit of Long's Peak (14,255 feet above sea-level) includes the inevitable and many-tinted lichens, spike-gra.s.s, dainty blue polemonium, and clumps of crimson purple primroses, all exquisitely beautiful. There are straggling b.u.mblebees, gra.s.shoppers, and at least two kinds of prettily robed b.u.t.terflies. Among the mammals visiting the summit I have seen a mountain lion, a bob-cat, a rabbit, and a silver fox, though only one of each. The bird callers embrace flocks of rosy finches, ptarmigan, and American pipits, and numbers of white-crowned sparrows and juncos, together with a scattering of robins, bluebirds, golden eagles, red-tailed hawks, and hummingbirds!
The summit life zone in the Rocky Mountains not only sweeps up to exceptionally high alt.i.tudes, but it embraces vast territory. In Colorado alone the Arctic-Alpine territory above the tree-line probably extends over five million or more acres. Thrust high in this summit area are the tops of more than three hundred peaks. Many of these tower three thousand feet above the timber-line. Much of this region is made up of steep slopes, shattered summits, and precipitous walls, many of which bound canons. There is a scattering of lakes, gentle slopes, stretches of rolling moorlands, and bits of wet meadow or arctic tundra. In this high and far-extending mountain land one may travel day after day always above the uppermost reaches of the forest.
In this strange treeless realm there is a largeness of view. Up close to the clouds and the sky, the big world far below, the scene stretches away in boundless, magnificent distances.
The snow-fall of this region varies with locality, and ranges from a few feet up to fifty feet annually. In most localities this snow is rapidly evaporated by the exceedingly dry air of the heights. The remnants of each year's fall commonly rest upon the acc.u.mulations of preceding years, but during midsummer not one tenth of the heights is snow-covered. Vast areas are occupied by craggy peaks and barren rock-fields. The barrenness is due almost entirely to a lack of soil, not to alt.i.tude nor to the rigors of the climate. The climate is in many respects similar to that which wraps the Arctic Circle near sea-level, and it allows many forms of vigorous life.
Numerous moraines, terraces, steppes, and moorlands--the wide sky plains--have their soil, and this in the warmth of summer generously produces green gra.s.s and brilliant flowers. These, together with big game, birds, and circling b.u.t.terflies, people this zone with life and turn the towering and terraced heights into the rarest of hanging wild gardens. In favored places for a mile or so above timber-line are scattered acres of heathy growths. Stunted by cold, clipped off by the wind, and heavily pressed by the snow, these growths are thickly tangled, bristly, and rarely more than a few inches in height. Among these are wintergreen, bunchberry, huckleberry, kalmia, currant, black birch, and arctic willow. There are miles of moorlands covered with short, thin gra.s.ses, while deeply soil-covered terraces, cozy slopes, and wet meadows have plushy gra.s.s carpets several inches thick. These growths form the basic food-supply of both the insects and the warm-blooded life of the heights.