Israel C. (Israel Cook) Russell.

Glaciers of North America; a reading lesson for students of geography and geology online

. (page 11 of 24)
Online LibraryIsrael C. (Israel Cook) RussellGlaciers of North America; a reading lesson for students of geography and geology → online text (page 11 of 24)
Font size
QR-code for this ebook

the fiord a few miles northeast of where Turner glacier terminates. This
ice stream, the most magnificent of the tide-water glaciers of Alaska yet
discovered (with the exception, as is now known, of the southwest pro-
longation of Malaspina glacier), and a towering mountain peak from which
it receives a large part of its drainage, were named in honor of Gardiner
G. Hubbard, president of the National Geographic Society. A dark head-
land on the shore of the mainland to the right shuts off the full view of
the glacier, but formed a strongly drawn foreground, which enhanced the
picturesque effect of the scenery."

A year later, on September 6, I renewed the exploration of Disenchant-
ment bay. With two companions I rowed northward near the base of the
cliffs to the east of Haenke island. We found the bay quite free from
floating ice, although the bergs were densely packed against the western
shore. The morning was bright and fresh after prolonged storms, but
dense cloud masses still clung to the cold summits of the higher moun-
tains. The vegetation on the rugged shores became more and more
stunted as we advanced. Before reaching Osier island, situated at the
abrupt angle formed where Disenchantment bay turns eastward, even the
more sheltered gorges were barren and desolate down to within 100 feet
of the water's edge. At Osier island there is an outstanding cape, form-
ing an island at high tide, which is covered with a dense growth of
stunted willows, hence its name, and affords a fine station for ob-
serving the magnificence of the surrounding glaciers and mountains.

Seated among the willows on the summit of the island, we noted the
luxuriance of the grasses at our feet and the profusion of dwarf rasp-
berries, Rubus arctica, which were just ripening. We were at the actual
border of vegetation. All to the north was stern, wild, and desolate.
Cliffs and precipices without the softening tints of plant life rose precipi-
tously from the water's edge to the snow-covered slopes which disap-
peared in the clouds. Just across the inlet, perhaps two miles distant,
rose the ice cliffs of Hubbard glacier to a height, by estimate, of 250 to
300 feet. Each shining buttress and glittering pinnacle, as seen in the
early morning light, was of the purest white or of the most delicate blue,
while the caves and deep recesses were of such a deep blue that they
appeared black in contrast with the sheen of the surfaces where the sun-
light fell. Reports like the roar of heavy guns frequently attracted our
attention to the cliffs, but owing to their distance, the avalanches causing
the disturbances usually disappeared before the sound reached our station.




(Drawn from a Photograph.)



Following the reports came the waves generated by the falling ice masses,
which broke on the beach in long lines of foam. The surface of the
bay was unruffled by wind, and the breaking of these occasional surges
seemed a phenomenon without a cause, until their connection with the
masses of ice falling from the glacier was suggested.

Both Turner and Hubbard glaciers are in full view from Osier island,
as are also many lesser ice streams that do not reach the sea. The lower
extremity of all of the smaller glaciers that approach the sea are com-
pletely concealed beneath brown and barren moraines. Many times these
sheets of debris are so uniform, and merge with the surrounding boulder-
covered area so gradually, that it is impossible to tell where the glaciers
actually terminate.

During our exploration of Disenchantment bay, we sailed eastward
along the coast to where the inlet abruptly changes its course and extends
southward through the mountains and into the flat, forest-covered alluvial
plain bordering the Pacific. At the angle where the bay makes this sharp
bend there is a high, rocky promontory of glacier-burnished rock, which I
named Cape Enchantment. From the summit of this headland another
splendid view of the mountain-enclosed bay was obtained. At the extreme
eastern end of the east-and-west reach of the bay, a large glacier comes
down to the water, and breaking off sends many bergs adrift. This
glacier was not explored, but evidently flows from snow fields far back in
the highlands. Near where it discharges into the bay it is divided by a
rounded dome of rock which rises through the ice and forms a nunatak,
as such islands in ice are called in Greenland, which suggested the name
Nunatak glacier.

Many other facts of interest to the student of glaciers may be observed
from Haenke and Osier islands and from Cape Enchantment, some of
which are described elsewhere. 1 As our immediate interest is concen-
trated on tide-water glaciers we must pass on, in our fireside travels, to the
next example, to the west of Yakutat bay, which is by far the most
magnificent of its class yet found in Alaska.


All of the tide-water glaciers of Alaska referred to above reach the
waters of the ocean at the heads of deep inlets or fiords, and are sur-

x "An Expedition to Mount St. Elias, 1890," National Geographic Magazine, vol. 3,
1801, pp. 53-203. " Second Expedition to Mount St. Elias, 1891," 13th Annual Report U.
S. Geological Survey, pp. 1-91.


rounded by precipitous mountains. At Icy cape, however, the western
lobe of Malaspma glacier advances boldly into the Pacific and meets the
full force of its surges. There are no highlands bordering the ocean for
scores of miles on either hand, and the glittering wall of ice rises above
the foaming waters to a height not less than three hundred feet. The
general appearance of these great precipices of ice when seen at a distance
recall the chalk cliffs of Dover, but are more varied in color and far more
impressive. The heavy waves of the Pacific undermine the cliffs, and
great masses of ice are almost continually falling into the sea. Their
thunder is seldom silent, and on still days can be heard distinctly at a
distance of twenty miles.

The scene presented by Icy cape, with its white girdle of floating
bergs, especially when a storm is raging and the heavy billows add their
roar to the thunder of the avalanches, is one of the wildest and grandest
that can be imagined.

The ice cliffs formed where Malaspina glacier enters the sea present
only one of the many interesting features of the great ice sheet at the
southern base of Mount St. Elias. This great glacier is the type of pied-
mont ice sheets, and will be described a few pages in advance.

To the west of Icy cape there are other great glaciers intervening be-
tween the mountains and the sea. The largest of these, known as Bering
glacier, is probably of the same character as the Malaspina ice sheet, but no
one has trodden its surface and scarcely anything is known concerning
even its more general features. So far as has been reported, there are no
glaciers to the west of Icy cape which actually reach the sea, and there-
fore none that require mention at the present time.


Several of the alpine glaciers of Alaska which enter the sea have
already been partially described under the head of tide-water glaciers ; but
there are others, numbering many hundred and probably several thou-
sand, that terminate before reaching the sea, and belong to the class here
considered. Nearly all of the higher valleys and depressions among the
mountains from Stikine river northward and westward to Cook's inlet are
filled with neve snows and drained by ice streams. This great glacial
belt, nearly a thousand miles in length, has its maximum width in the
vicinity of Mounts Fairweather, Logan, and St. Elias, where it is from 80
to 100 miles wide. Over this central territory, about 350 miles in length,


every depression at an elevation of over a thousand fee't, is filled with
snow and ice, making one confluent neve field, through which the higher
and more rugged peaks rise like barren islands. An extended view of
this wild country, where so many glaciers have their sources, was obtained
by the writer in August, 1891, from the northern side of Mount St. Elias,
and may be taken as representing the general- character of the entire
region between Lynn canal and Copper river. My report on the portion
of the climb referred to is as follows 1 :

" I was now so near the crest of the divide that only a few yards re-
mained before I should be able to see the country to the north, a vast
region which no one had yet beheld. As I passed on, I pictured in fancy
its character. Having previously crossed this same system of mountains
at the head of Lynn canal and traversed the country north of it, I imagined
I should behold a similar region north of Mount St. Elias. I expected to
see a comparatively low, forested country, stretching away to the north,
with lakes and rivers and perhaps some signs of human habitation ; but I
was entirely mistaken. What met my astonished gaze was a vast snow-
covered region, limitless in expanse, through which hundreds and perhaps
thousands of barren, angular mountain peaks projected. There was not a
stream, not a lake, and not a vestige of vegetation of any kind in sight.
A more desolate or a more utterly lifeless land one never beheld. Vast
smooth snow surfaces, without crevasses, stretched away to limitless
distances, broken only by jagged and angular mountain peaks. The
general elevation of the snow surface is about 8000 feet, and the moun-
tains piercing it are from 10,000 to 12,000 feet, or more, in altitude above
the sea. Northward I could see every detail in the forbidding landscape
for miles and miles. The most remote peaks in view in that direction
were 40 or 50 miles distant. To the southeast rose Mount Fairweather,
plainly distinguishable, although 200 miles away. About an equal dis-
tance to the northwest are two prominent mountain ranges, the highest
peaks of which appeared as lofty as Mount Fairweather. These must be
in the vicinity of Mount Wrangel, but their summits were unclouded
and gave no token of volcanic activity.

"I could look down upon the coast about Yakutat bay and distin-
guish each familiar island and headland. The dark shade on the shore,
too distant to reveal its nature, I knew was due to the dense forests on
the lowlands between the mountains and the sea. This was the only

!" Second Expedition to Mount St. Elias, 1891," in 13th Annual Report U. S. Geologi-
cal Survey, 1891-92, pp. 47, 48.


indication of vegetation in all the vast landscape that lay spread out
beneath my feet. The few rocks near at hand, which projected above the
snow, were without the familiar tints of mosses and lichens. Even the
ravens which sometimes haunt the higher mountains were nowhere to be
seen. Utter desolation claimed the entire land.

" The view to the north called to mind the pictures given by Arctic
explorers of the borders of the great Greenland ice sheet, where rocky
islands, known as 'nunataks,' alone break the monotony of the boundless
sea of ice. The region before me was a land of nunataks."

It is impossible to give a detailed account of the great number of
alpine glaciers in southern Alaska, but a few of those best known may
be described, and serve as examples of the class to which they belong.

Seward Glacier. The largest alpine glacier thus far discovered in
North America, exclusive of the Greenland region, has its source in the
neighborhood of Mount Logan, and was named the Seward glacier in
honor of the distinguished Secretary, to whom we are indebted for the
purchase of Alaska. It has many tributaries in the rugged region where
it rises, and flows southward like a broad sluggish river to the Malaspina
glacier, of which it is one of the principal feeders. A portion of this great
glacier and some of its branches, is shown on the map forming Plate
but the entire area it drains has not been explored. A view of the glacier
and of many of its tributaries was had by the writer from the summit of
the Pinnacle cliffs, which embraced fully fifty miles of the ice stream and
many of the magnificent peaks from which it receives the snow drainage.
The glacier in its narrowest part is by estimate three miles broad. Ex-
cept at a few places where it passes rocky precipices, its sides are poorly
defined, as it merges with broad snow fields in such a manner that only
the crevassed and broken condition of the snow on the sides of the more
rapidly flowing central portion serves to define its boundaries. At three
localities where it descends steep slopes due to faults in the rocks beneath,
the ice is broken and stands in pinnacles between blue crevasses, but
these ice falls are not as high or as impressive as in some of the neighbor-
ing glaciers. The first or upper fall, at the east end of the Corwin cliffs,
is an abrupt descent of several hundred feet, and from the west appears
like a huge wall crossing the glacier from side to side. Both above and
below the fall the surface appears nearly level for several miles, and is as
smooth and even as a snow-covered meadow. Some ten miles below the
upper fall is the second ice cascade, or what may more properly be called


an ice rapid. The ice is there greatly crevassed for several miles, but
retains a general^ level surface and its remarkably stream-like character.
These rapids occur whPT-e the ice flows across an escarpment formed by a
prolongation of Pinnacle cliffs.

On looking down e-n the rapids from a commanding summit, one be-
holds a series of breaks in the ice which are small at first and trend up
stream from each margin of the central curreiit. The first breaks to be
recognized are mere cracks, and although approaching the center of the
glacier, do not meet. A few rods below, the cracks are a little broader,
and meet in the center of the glacier so as to form a continuous break from
side to side. The fissures from either side meet at an angle of perhaps 50
or 60 degrees, and form V-shaped figures, with their apexes pointing up
stream. A few rods farther down, the crevasses cross the glacier in nearly
straight lines, and then begin to bow in the middle on account of the more
rapid central current. The more rapid flow of the central portion of the
stream is indicated throughout the descent by the curvature of the crevasses.
After becoming gently curved down stream they pass into semilunar
gashes, widest in the center and tapering toAvards the end. Finally, near
the lower end of the rapid, the crescents become sharply bent in the
center, and the bending increases until the gashes from either side unite
at an angle of perhaps 30 degrees, and again form V-shaped figures, this
time pointing down stream. With these progressive changes in the direc-
tion and size of the crevasses, cross fractures are formed, which become
more and more numerous in the central and lower portions of the rapid.
The parallel V-shaped gashes arranged in regular order, one above
another, impart to the central part of the glacier a peculiar wavy appear-
ance when seen from a distance, resembling the changeable figures to be seen
in " watered ribbon." With these changes in the direction and size of the
crevasses there are accompanying changes in color. The cracks in the
upper part of the rapids are in a white surface, but the ice forming their
walls is dark blue. At a distance the breaks appear as blue lines on the
snow. Lower down stream, where the cracks become wider, broad white
tables are left between them. As cross fractures are formed, the sides of
the tables crumble away and portions falling into the crevasses tend to fill
them up. As the surface melts, the surfaces of the tables lose their purity
and become dust-covered and yellowish, but the broken blocks in the
crevasses expose fresh material and retain their whiteness. At this stage,
the sides of the crevasses change from blue to white. The positions of the
breaks are then marked by broad, white bands on a gray surface. Far


down the rapids, where the lower set of V-shaped crevasses are most pro-
nounced, the tables have crumbled away and filled the intervening gulfs,
so that their positions are distinguished solely by differences in color.
The scars of the crevasses formed above are shown by white bands on a
dark, dust and dirt covered surface, instead of by blue markings on a white
surface, as at the beginning. Before the lower ice fall is reached where
the Seward glacier makes a final plunge before joining the Malaspina
glacier, nearly all traces of the tens of thousands of fissures formed above
have disappeared.

An observer standing on one of the commanding summits at the western
end of Pinnacle cliffs can see the broad surface of Seward glacier from
the upper falls to where it disappears over the brink of the lower fall on
the border of Malaspina glacier. The glacier from side to side then drops
from sight, and the wild assemblage of pinnacles that occurs below is, only
indicated by a line of blue where the final plunge begins. Such a view
suggests the appearance of Niagara when seen from above the horseshoe
fall, but the far mightier cascade in the Seward glacier is silent and
apparently motionless.

The writer was encamped for several days in July, 1890, on a narrow
crest of rock barely wide enough to support a small tent, which breaks
through the snow at the western end of Pinnacle cliffs ; and on the imme-
diate border of the rapids is Seward glacier. The murmur of water flow-
ing through icy channels could be heard far beneath the surface of the
glacier, but no streams traversed its broken surface. Crashes and rum-
bling noises produced by the slowly moving mass frequently attracted our
attention, and sometimes at night we would be awakened by a dull, heavy
thud, accompanied by a trembling of the rocks on which we slept, and
producing the effect of a slight earthquake shock. Occasionally a tower-
ing pinnacle of ice on the extremely rugged surface of the glacier in front
of our tent would fall with a startling crash and be engulfed in an ad-
jacent crevass. These evidences of change showed that the apparently
motionless ice was in reality flowing onward. Changes in the relative
positions of easily recognized points on the glacier and on the distant
shore were noticed during various visits, but instrumental measurements
of the rate of motion of various prominent pinnacles made by my assistant
and myself failed to give satisfactory results.

When exploration shall be extended into the mountains clustering
about Mount Logan and extending northward from Mount St. Elias, the
Seward glacier will furnish the most promising highway of travel. The




The summit of Mount St. Elias is seen in the distance, beyond the hills bordering the glacier.
(Drawn from a Photograph.)



snow fields along the margins of the glacier where its surface is most
broken afford easy lines of march, and the ice falls can be passed without
serious difficulty by scaling the adjacent cliffs. When once above the
upper fall the way is clear, and a broad, snow-covered surface affords a
direct route to the immediate base of Mount Logan. In making this
journey the explorer should pass around the southern end of the Hitch-
cock range and gain the Seward glacier just above the lower fall. When
that point is reached the way ahead is well defined. By means of snow
shoes and sleds drawn by dogs, an advance can be made for perhaps a hun-
dred miles into the interior. By descending a glacier on the northern
side of the mountains some stream could be reached which would carry the
explorer again to the coast. The close of the winter season would prob-
ably be the best for this attractive journey, as the crevasses would then
be deeply buried, and the rivers of the interior could be reached in time
to descend them during the short summer.

Although Seward glacier is the largest ice stream yet discovered in
Alaska, it does not differ materially from many others of the same type
now known to exist in that region. It is the only glacier in the neigh-
borhood of Mount St. Elias, however, which, so far as known, heads far
back in the mountain and flows through a low-grade pass to the sea. The
Hubbard glacier may have this characteristic, but as its gathering-ground
has never been seen, its relation to the mountain cannot be definitely
determined. The character of the surface of the Seward glacier is shown
on Fig. A, Plate 16 ; the summit of the upturned mountain-block
forming Mount St. Elias is seen beyond the hills forming the bank
of the glacier.

The next large ice stream to the west of the Seward glacier is the Agassiz
glacier, which drains the snow fields on the south side of the Augusta
range and the eastern slope of Mount St. Elias. To the west of Mount
St. Elias rises Guyot glacier, another of the great tributaries that unite to
form the Malaspina ice sheet, the type of piedmont glaciers.


It has been the writer's good fortune to make three trips through
Lynn canal, each of which furnished many independent observations on
the glaciers diversifying its shores. The first of these journeys was made
in a canoe with a single Indian, while returning from an expedition up
the Yukon river, an account of which has been published in the Bulletin


of the Geological Society of America. 1 The second and third journeys
were made on steamers and were much less satisfactory than the first.

Taya Inlet. Lynn canal divides near its head into two arms, known
as Taya and Chilkat inlets. The first leads toward Chilhoot pass and
the second toward Chilkat pass. Each of these arms, like the main
trunk of Lynn canal, is bordered by high mountains, and receives many
swift streams issuing from caves at the lower extremities of alpine
glaciers. The larger glaciers drain broad neve fields which whiten the
higher portions of the mountains throughout the year. The smaller ones
have their sources in sheltered amphitheatres and cirques, but at times
originate in snow fields that rest on the mountain side, and are so promi-
nent that when seen in profile, they give a convex outline to the sides of
the peaks about which they cluster.

From a mountain top about 3000 feet high, on the west side of Taya
inlet, I obtained an extensive and most instructive view of the rugged
mountains in which the blue tranquil waters of the great canal are em-
bosomed. From one station I counted nearly forty glaciers, and a change
in position of half a mile brought several others into view which before
were concealed by rugged crags and snow-covered slopes near at hand.
The outlines of vast amphitheatres in the mountain tops could be traced by
lines of pinnacles and towering, frost-riven crags forming their rims, but
the basins within were so deeply filled with snow and ice that one could
walk across them with ease. Many of the views of the mountains enclos-
ing Lynn canal, obtained from the decks of steamers, are truly magnifi-
cent, but fail to give such a comprehensive idea of the entire plan of the
hundreds of snow-clad peaks, and of the deep valleys separating them, as
the broad panoramas which reward the climber who reaches some of the
less aspiring summits. Added to the sublime picture of snowy ranges
and winding waterways obtained from such a station are wonderful cloud
effects, to be seen especially when a storm gives way to clear skies and the
last remnant of the vapory hosts that previously enshrouded the ranges
still cling to the more lofty summits.

Davidson Glacier. The finest glacier on Lynn canal, named in
honor of Prof. George Davidson, of the U. S. Coast and Geodetic Survey,
has its source in the rugged mountains between Lynn canal and Glacier
bay, and flows from the same general neve fields that supply some of the
principal tributaries of Muir glacier. A photograph of its expanded ex-

iVol. 1, 1890, pp. 99-162.


tremity, as seen from a passing vessel, is reproduced in Fig. B, Plate 16.
It finds its way eastward through a deep, high-grade gorge between lofty
peaks, and reaches within a few score feet of sea level, but does not enter
the waters of the canal so as to form a tide- water glacier. Moraines left

1 2 3 4 5 6 7 8 9 11 13 14 15 16 17 18 19 20 21 22 23 24

Online LibraryIsrael C. (Israel Cook) RussellGlaciers of North America; a reading lesson for students of geography and geology → online text (page 11 of 24)