Popular Science Monthly/Volume 35/June 1889/Glaciers on the Pacific Coast
|GLACIERS ON THE PACIFIC COAST.|
NORTHWARD from Washington Territory the coast is everywhere very rugged, being formed by the lofty peaks of an extension of the Cascade Range; while the thousands of islands which fringe the coast of British Columbia and Alaska are but the partially submerged peaks of an extension of the Coast Range, from which the great glaciers of former times have scraped off nearly all the fertile soil. It is estimated that there are ten thousand islands between Washington Territory and Mount St. Elias, and all the larger of them bear snow-covered summits during the whole year. The water in the narrow channels separating these islands is ordinarily several hundred feet deep, affording, through nearly the whole distance, a protected channel for navigation.
Three great rivers interrupt the mountain barrier of British Columbia facing the Pacific—the Eraser, the Skeena, and the Stickeen—and the interior is penetrated for some distance by innumerable fiords. The Canadian Pacific Railroad follows the course of the Eraser for a long distance, and passes within sight of glaciers of considerable extent, and every fiord receives the drainage of numerous decaying glaciers. But it is not until reaching the Stickeen River, in Alaska, in latitude 57°, that glaciers begin to
Fig. 1.—Glacier Station Selkirk Mountains, British Columbia. (Courtesy of the Canadian Pacific Railroad.
appear which are both easily accessible and large enough to invite protracted study. The water coming into the sound from the Stickeen River is heavily charged with glacial mud, which spreads itself out over a great expanse. An extensive delta, forming almost the
only arable land in southeastern Alaska, has been built up by the deposit at the mouth of this river. The most accurate information yet obtained concerning these glaciers is that gathered by Mr. William P. Blake in 1863. According to him, "there are four large glaciers and several smaller ones visible within a distance of sixty or seventy miles from the mouth" of the river. The second of these larger ones has attracted most attention. This "sweeps grandly out into the valley from an opening between high mountains from a source that is not visible. It ends at the level of the river in an irregular bluff of ice, a mile and a half or two miles in length, and about one hundred and fifty feet high. Two or more terminal moraines protect it from the direct action of the stream. What at first appeared as a range of ordinary hills along the river, proved on landing to be an ancient terminal moraine, crescent shaped and covered with a forest. It extends the full length of the front of the glacier."
This glacier has never been fully explored. A number of years since, a party of Russian officers attempted its exploration, and were never heard from again. Mr. Blake reports that, as usual with receding glaciers, a considerable portion of the front as it spreads out in the valley is so covered with bowlders, gravel, and mud that it is difficult to tell where the glacier really ends. But from the valley to the higher land it rises in precipitous, irregular, stair-like blocks, with smooth sides, and so large that it was impossible to surmount them with the Ordinary equipment of explorers. The glacier is estimated to be about forty miles long.
Another glacier, upon the opposite side of the river, of which Mr. Blake does not speak, was reported to me by those familiar with the country as coming down to within about two miles of the bank. The Indians are very likely correct in asserting that these two glaciers formerly met, compelling the Stickeen River to find its way to the sea through a vast tunnel. It would then have appeared simply as a subglacial stream of great magnitude.
North of the Stickeen River, glaciers of great size are of increasing frequency, and can be seen to good advantage from the excursion steamer. The Auk and Patterson glaciers appear first, not far north of Fort Wrangel. On approaching Holkham Bay and Taku Inlet, about latitude 58°, the summer tourist has, in the numerous icebergs encountered, pleasing evidence of the proximity of still greater glaciers coming down to the sea-level. Indeed, the glaciers of Taku Inlet are second only in interest to those of Glacier Bay.
In going from Juneau to edge, and has there built up an immense terminal moraine all along its front., at the head of Lynn Canal, a distance of about eighty miles, nineteen glaciers of large size are in full sight from the steamer's deck, but none of them come down far enough to break off into the water and give birth to icebergs. The Davidson Glacier, however, comes down just to the water's
Fig. 3.—Norris Glacier, Taku Inlet, Alaska. Showing icebergs that have broken off from the front. Front about one mile wide. (Photograph by Partridge.)
An illustration of the precipitous character of the southeastern coast of Alaska is seen in the fact that it is only thirty-five miles from the head of Lynn Canal to the sources of the Yukon River, which then flows to the north and west for nearly three thousand miles before coming down to the sea-level. Lieutenant Schwatka reports four glaciers of considerable size in the course of this short portage between Chilkat and Lake Lindeman. The vast region through which the Yukon flows to the north of these mountains is not known to contain any extensive glaciers. But, according to the reports of Dall, Schwatka, and others, it is a most inhospitable country, where human life can be maintained only with the greatest difficulty; where the thermometer sinks to 60° below zero in winter, and rises for a short period to 120° in the summer; and where the ground remains perpetually frozen at a short depth below the surface.
Fig. 4.—Davidson Glacier, near Chilkat, Alaska, latitude 59° 45'. The mountains are from five thousand to seven thousand feet high; the gorge about three quarters of a mile wide; the front of the glacier, three miles; the terminal moraine, about two hundred and fifty feet high. (View from two miles distant.)
From Cross Sound, about latitude 58° and longitude 136° west from Greenwich, to the Alaskan Peninsula, the coast is bordered by a most magnificent semicircle of mountains opening to the south, and extending for more than a thousand miles. Throughout this whole extent, glaciers of large size are everywhere to be seen. Elliott estimates that, counting great and small, there can not be less than five thousand glaciers between Dixon's Entrance and the extremity of the Alaskan Peninsula.
Little is known in detail of the glaciers of this region. But those in the neighborhood of Mount St. Elias are evidently the largest anywhere to be found in the northern hemisphere outside of Greenland. This mountain rises 19,500 feet above the sea; and Lieutenant Schwatka, in his expedition of 1886, reported eleven glaciers as coming down from its southern side. One of these, which is named the Agassiz Glacier, he estimates to be twenty miles in width and fifty miles in length, and to cover an area of a thousand square miles. Another, which he named Guyot Glacier, seemed to be about the same in dimensions. These come down to the sea-level in Icy Bay, and present a solid ice wall many miles in extent, which is continually breaking off into icebergs of great size.
Vancouver's account of the glacial phenomena along this coast is still both instructive and interesting, and in places curious:
"Between these points (Pigot and Pakenham) a bay is formed, about a league and a half deep toward the north-northwest, in which were seen several shoals and much ice; the termination of this bay is bounded by a continuation of the above range of lofty mountains. On this second low projecting point, which Mr. Whidbey called 'Point Pakenham,' the latitude was observed to be 60° 591', its longitude 212° 29'. The width of the arm at this station was reduced to two miles, in which were several half-concealed rocks, and much floating ice, through which they pursued their examination, to a point at the distance of three miles along the western shore, which still continued to be compact, extending north 30° east; in this direction they met such innumerable huge bodies of ice, some afloat, others lying on the ground near the shore in ten or twelve fathoms water, as rendered their further progress up the branch rash and highly dangerous. This was, however, very fortunately, an object of no moment, since before their return they had obtained a distinct view of its termination, about two leagues farther in the same direction, by a firm and compact body of ice reaching from side to side, and greatly above the level of the sea; behind which extended the continuation of the same range of lofty mountains, whose summits seemed to be higher than any that had yet been seen on the coast.
"While at dinner in this situation they frequently heard a very loud, rumbling noise, not unlike loud but distant thunder; similar sounds had often been heard when the party was in the neighborhood of large bodies of ice, but they had not before been able to trace the cause. They now found the noise to originate from immense ponderous fragments of ice, breaking off from the higher parts of the main body, and falling from a very considerable height, which in one instance produced so violent a shock that it was sensibly felt by the whole party, although the ground on which they were was at least two leagues from the spot where the fall of ice had taken place. . . .
"The base of this lofty range of mountains (between Elias and Fair weather) now gradually approached the sea-side; and to the southward of Cape Fairweather it may be said to be washed by the ocean; the interruption in the summit of these very elevated mountains, mentioned by Captain Cook, was likewise conspicuously evident to us as we sailed along the coast this day, and looked like a plain composed of a solid mass of ice or frozen snow, inclining gradually toward the low border; which from the smoothness, uniformity, and clean appearance of its surface, conveyed the idea of extensive waters having once existed beyond the then limits of our view, which had passed over this depressed part of the mountains, until their progress had been stopped by the severity of the climate, and that,> by the accumulation of succeeding snow, freezing on this body of ice, a barrier had become formed that had prevented such waters from flowing into the sea. This is not the only place where we had noticed the like appearance; since passing the icy bay mentioned on the 28th of June, other valleys had been seen strongly resembling this, but none were so extensive, nor was the surface of any of them so clean, most of them appearing to be very dirty. I do not, however, mean to assert that these inclined planes of ice must have been formed by the passing of inland waters thus into the ocean, as the elevation of them, which must be many hundred yards above the level of the sea, and their having been doomed for ages to perpetual frost, operate much against this reasoning; but one is naturally led, on contemplating any phenomenon out of the ordinary course of nature, to form some conjecture and to hazard some opinion as to its origin, which on the present occasion is rather offered for the purpose of describing its appearance, than accounting for the cause of its existence."
Beyond Mount St. Elias, in the neighborhood of the Copper River and Prince William Sound, glaciers are reported by Elliott as numerous and of great size. Mount Wrangel, in the forks of the Copper River, is estimated by him to be upward of twenty thousand feet in height. From the flanks of the Chugatch Alps, of which Wrangel is the eastern summit, immense glaciers descend to Prince William Sound, and add greatly to the gloomy grandeur of its scenery. Glaciers also extend throughout the Kenai and Alaskan Peninsulas, as far to the westward as longitude 162°, and one even has been observed upon the island of Unalaska.
The region in the interior north of the St. Elias and Chugatch Alps has been but imperfectly explored; but there seems pretty general agreement that there are no glaciers there at the present time, nor is there evidence that glaciers ever existed in the country. Much of the region is now covered with tundra—that is, with vast level areas which are so deeply frozen that they never thaw out below a few feet from the surface. These are covered with a dense growth of heath and arctic mosses, which afford food for the reindeer, but are useless for man.
At Eschscholtz Bay, on Kotzebue Sound, in latitude 66° 15,' Kotzebue discovered in 1818 a cliff of frozen mud and ice "capped by a few feet of soil bearing moss and grass." Large numbers of bones of the "mammoth, bison (?), reindeer, moose-deer, musk-ox, and horse, were found" at the base, where they had fallen down from the cliff during the summer thaw. Sir Edward Belcher and Mr. G. B. Seeman afterward visited the same spot and corroborated Kotzebue's account. From their report it was evident that the conditions in northern Alaska are very similar to those in northern Siberia, where so many similar remains of extinct and other animals have been found in the frozen soil. The section described at Eschscholtz Bay seems to be simply the edge of the tundra which is so largely represented in the central portions of the Territory.
- From advance sheets of "The Ice Age in North America, and its Bearings on the Antiquity of Man." In press of D. Appleton & Co.
- "American Journal of Science," vol. xciv, 1867, pp. 96-101.
- "Science," vol. iii (February 22, 1884), pp. 220-227.
- See "Our Arctic Province," p. 91.
- "New York Times," November 14, 1886.
- "Voyage of Discovery around the "World, vol. v, pp. 312-314, 358-360.
- See Prestwich's "Geology," vol. ii, p. 463 et seq.