THE SNOW
The first snow that whitens the Sierra, usually falls about the end of
October or early in November, to a depth of a few inches, after months
of the most charming Indian summer weather imaginable. But in a few
days, this light covering mostly melts from the slopes exposed to the
sun and causes but little apprehension on the part of mountaineers who
may be lingering among the high peaks at this time. The first general
winter storm that yields snow that is to form a lasting portion of the
season’s supply, seldom breaks on the mountains before the end of
November. Then, warned by the sky, cautions mountaineers, together with
the wild sheep, deer, and most of the birds and bears, make haste to
the lowlands or foot-hills; and burrowing marmots, mountain beavers,
wood-rats, and such people go into winter quarters, some of them not
again to see the light of day until the general awakening and
resurrection of the spring in June or July. The first heavy fall is
usually from about two to four feet in depth. Then, with intervals of
splendid sunshine, storm succeeds storm, heaping snow on snow, until
thirty to fifty feet has fallen. But on account of its settling and
compacting, and the almost constant waste from melting and evaporation,
the average depth actually found at any time seldom exceeds ten feet in
the forest region, or fifteen feet along the slopes of the summit
peaks.
Even during the coldest weather evaporation never wholly ceases, and
the sunshine that abounds between the storms is sufficiently powerful
to melt the surface more or less through all the winter months. Waste
from melting also goes on to some extent on the bottom from heat stored
up in the rocks, and given off slowly to the snow in contact with them,
as is shown by the rising of the streams on all the higher regions
after the first snowfall, and their steady sustained flow all winter.
The greater portion of the snow deposited around the lofty summits of
the range falls in small crisp flakes and broken crystals, or, when
accompanied by strong winds and low temperature, the crystals, instead
of being locked together in their fall to form tufted flakes, are
beaten and broken into meal and fine dust. But down in the forest
region the greater portion comes gently to the ground, light and
feathery, some of the flakes in mild weather being nearly an inch in
diameter, and it is evenly distributed and kept from drifting to any
great extent by the shelter afforded by the large trees. Every tree
during the progress of gentle storms is loaded with, fairy bloom at the
coldest and darkest time of year, bending the branches, and hushing
every singing needle. But as soon as the storm is over, and the sun
shines, the snow at once begins to shift and settle and fall from the
branches in miniature avalanches, and the white forest soon becomes
green again. The snow on the ground also settles and thaws every bright
day, and freezes at night, until it becomes coarsely granulated, and
loses every trace of its rayed crystalline structure, and then a man
may walk firmly over its frozen surface as if on ice. The forest region
up to an elevation of 7000 feet is usually in great part free from snow
in June, but at this time the higher regions are still heavy-laden, and
are not touched by spring weather to any considerable extent before the
middle or end of July.
One of the most striking effects of the snow on the mountains is the
burial of the rivers and small lakes.
As the snow fa’s in the river
A moment white, then lost forever,
sang Burns, in illustrating the fleeting character of human pleasure.
The first snowflakes that fall into the Sierra rivers vanish thus
suddenly; but in great storms, when the temperature is low, the
abundance of the snow at length chills the water nearly to the
freezing-point, and then, of course, it ceases to melt and consume the
snow so suddenly. The falling flakes and crystals form, cloud-like
masses of blue sludge, which are swept forward with the current and
carried down to warmer climates many miles distant, while some are
lodged against logs and rocks and projecting points of the banks, and
last for days, piled high above the level of the water, and show white
again, instead of being at once “lost forever,” while the rivers
themselves are at length lost for months during the snowy period. The
snow is first built out from the banks in bossy, over-curling drifts,
compacting and cementing until the streams are spanned. They then flow
in the dark beneath a continuous covering across the snowy zone, which
is about thirty miles wide. All the Sierra rivers and their tributaries
in these high regions are thus lost every winter, as if another glacial
period had come on. Not a drop of running water is to be seen excepting
at a few points where large falls occur, though the rush and rumble of
the heavier currents may still be heard. Toward spring, when the
weather is warm during the day and frosty at night, repeated thawing
and freezing and new layers of snow render the bridging-masses dense
and firm, so that one may safely walk across the streams, or even lead
a horse across them without danger of falling through. In June the
thinnest parts of the winter ceiling, and those most exposed to
sunshine, begin to give way, forming dark, rugged-edged, pit-like
sinks, at the bottom of which the rushing water may be seen. At the end
of June only here and there may the mountaineer find a secure
snow-bridge. The most lasting of the winter bridges, thawing from below
as well as from above, because of warm currents of air passing through
the tunnels, are strikingly arched and sculptured; and by the
occasional freezing of the oozing, dripping water of the ceiling they
become brightly and picturesquely icy. In some of the reaches, where
there is a free margin, we may walk through them. Small skylights
appearing here and there, these tunnels are not very dark. The roaring
river fills all the arching way with impressively loud reverberating
music, which is sweetened at times by the ouzel, a bird that is not
afraid to go wherever a stream may go, and to sing wherever a stream
sings.
All the small alpine pools and lakelets are in like manner obliterated
from the winter landscapes, either by being first frozen and then
covered by snow, or by being filled in by avalanches. The first
avalanche of the season shot into a lake basin may perhaps find the
surface frozen. Then there is a grand crashing of breaking ice and
dashing of waves mingled with the low, deep booming of the avalanche.
Detached masses of the invading snow, mixed with fragments of ice,
drift about in sludgy, island-like heaps, while the main body of it
forms a talus with its base wholly or in part resting on the bottom of
the basin, as controlled by its depth and the size of the avalanche.
The next avalanche, of course, encroaches still farther, and so on with
each in succession until the entire basin may be filled and its water
sponged up or displaced. This huge mass of sludge, more or less mixed
with sand, stones, and perhaps timber, is frozen to a considerable
depth, and much sun-heat is required to thaw it. Some of these
unfortunate lakelets are not clear of ice and snow until near the end
of summer. Others are never quite free, opening only on the side
opposite the entrance of the avalanches. Some show only a narrow
crescent of water lying between the shore and sheer bluffs of icy
compacted snow, masses of which breaking off float in front like
icebergs in a miniature Arctic Ocean, while the avalanche heaps leaning
back against the mountains look like small glaciers. The frontal cliffs
are in some instances quite picturesque, and with the berg-dotted
waters in front of them lighted with sunshine are exceedingly
beautiful. It often happens that while one side of a lake basin is
hopelessly snow-buried and frozen, the other, enjoying sunshine, is
adorned with beautiful flower-gardens. Some of the smaller lakes are
extinguished in an instant by a heavy avalanche either of rocks or
snow. The rolling, sliding, ponderous mass entering on one side sweeps
across the bottom and up the opposite side, displacing the water and
even scraping the basin clean, and shoving the accumulated rocks and
sediments up the farther bank and taking full possession. The dislodged
water is in part absorbed, but most of it is sent around the front of
the avalanche and down the channel of the outlet, roaring and hurrying
as if frightened and glad to escape.
SNOW-BANNERS
The most magnificent storm phenomenon I ever saw, surpassing in showy
grandeur the most imposing effects of clouds, floods, or avalanches,
was the peaks of the High Sierra, back of Yosemite Valley, decorated
with snow-banners. Many of the starry snow-flowers, out of which these
banners are made, fall before they are ripe, while most of those that
do attain perfect development as six-rayed crystals glint and chafe
against one another in their fall through the frosty air, and are
broken into fragments. This dry fragmentary snow is still further
prepared for the formation of banners by the action of the wind. For,
instead of finding rest at once, like the snow which falls into the
tranquil depths of the forests, it is rolled over and over, beaten
against rock-ridges, and swirled in pits and hollows, like boulders,
pebbles, and sand in the pot-holes of a river, until finally the
delicate angles of the crystals are worn off, and the whole mass is
reduced to dust. And whenever storm-winds find this prepared snow-dust
in a loose condition on exposed slopes, where there is a free upward
sweep to leeward, it is tossed back into the sky, and borne onward from
peak to peak in the form of banners or cloudy drifts, according to the
velocity of the wind and the conformation of the slopes up or around
which it is driven. While thus flying through the air, a small portion
makes good its escape, and remains in the sky as vapor. But far the
greater part, after being driven into the sky again and again, is at
length locked fast in bossy drifts, or in the wombs of glaciers, some
of it to remain silent and rigid for centuries before it is finally
melted and sent singing down the mountainsides to the sea.
Yet, notwithstanding the abundance of winter snow-dust in the
mountains, and the frequency of high winds, and the length of time the
dust remains loose and exposed to their action, the occurrence of
well-formed banners is, for causes we shall hereafter note,
comparatively rare. I have seen only one display of this kind that
seemed in every way perfect. This was in the winter of 1873, when the
snow-laden summits were swept by a wild “norther.” I happened at the
time to be wintering in Yosemite Valley, that sublime Sierra temple
where every day one may see the grandest sights. Yet even here the wild
gala-day of the north wind seemed surpassingly glorious. I was awakened
in the morning by the rocking of my cabin and the beating of pine-burs
on the roof. Detached torrents and avalanches from the main wind-flood
overhead were rushing wildly down the narrow side cañons, and over the
precipitous walls, with loud resounding roar, rousing the pines to
enthusiastic action, and making the whole valley vibrate as though it
were an instrument being played.
But afar on the lofty exposed peaks of the range standing so high in
the sky, the storm was expressing itself in still grander characters,
which I was soon to see in all their glory. I had long been anxious to
study some points in the structure of the ice-cone that is formed every
winter at the foot of the upper Yosemite fall, but the blinding spray
by which it is invested had hitherto prevented me from making a
sufficiently near approach. This morning the entire body of the fall
was torn into gauzy shreds, and blown horizontally along the face of
the cliff, leaving the cone dry; and while making my way to the top of
an overlooking ledge to seize so favorable an opportunity to examine
the interior of the cone, the peaks of the Merced group came in sight
over the shoulder of the South Dome, each waving a resplendent banner
against the blue sky, as regular in form, and as firm in texture, as if
woven of fine silk. So rare and splendid a phenomenon, of course,
overbore all other considerations, and I at once let the ice-cone go,
and began to force my way out of the valley to some dome or ridge
sufficiently lofty to command a general view of the main summits,
feeling assured that I should find them bannered still more gloriously;
nor was I in the least disappointed. Indian Cañon, through which I
climbed, was choked with snow that had been shot down in avalanches
from the high cliffs on either side, rendering the ascent difficult;
but inspired by the roaring storm, the tedious wallowing brought no
fatigue, and in four hours I gained the top of a ridge above the
valley, 8000 feet high. And there in bold relief, like a clear
painting, appeared a most imposing scene. Innumerable peaks, black and
sharp, rose grandly into the dark blue sky, their bases set in solid
white, their sides streaked and splashed with snow, like ocean rocks
with foam; and from every summit, all free and unconfused, was
streaming a beautiful silky silvery banner, from half a mile to a mile
in length, slender at the point of attachment, then widening gradually
as it extended from the peak until it was about 1000 or 1500 feet in
breadth, as near as I could estimate. The cluster of peaks called the
“Crown of the Sierra,” at the head of the Merced and Tuolumne
rivers,—Mounts Dana, Gibbs, Conness, Lyell, Maclure, Ritter, with their
nameless compeers,—each had its own refulgent banner, waving with a
clearly visible motion in the sunglow, and there was not a single cloud
in the sky to mar their simple grandeur. Fancy yourself standing on
this Yosemite ridge looking eastward. You notice a strange garish
glitter in the air. The gale drives wildly overhead with a fierce,
tempestuous roar, but its violence is not felt, for you are looking
through a sheltered opening in the woods as through a window. There, in
the immediate foreground of your picture, rises a majestic forest of
Silver Fir blooming in eternal freshness, the foliage yellow-green, and
the snow beneath the trees strewn with their beautiful plumes, plucked
off by the wind. Beyond, and extending over all the middle ground, are
somber swaths of pine, interrupted by huge swelling ridges and domes;
and just beyond the dark forest you see the monarchs of the High Sierra
waving their magnificent banners. They are twenty miles away, but you
would not wish them nearer, for every feature is distinct, and the
whole glorious show is seen in its right proportions. After this
general view, mark how sharply the dark snowless ribs and buttresses
and summits of the peaks are defined, excepting the portions veiled by
the banners, and how delicately their sides are streaked with snow,
where it has come to rest in narrow flutings and gorges. Mark, too, how
grandly the banners wave as the wind is deflected against their sides,
and how trimly each is attached to the very summit of its peak, like a
streamer at a masthead; how smooth and silky they are in texture, and
how finely their fading fringes are penciled on the azure sky. See how
dense and opaque they are at the point of attachment, and how filmy and
translucent toward the end, so that the peaks back of them are seen
dimly, as though you were looking through ground glass. Yet again
observe how some of the longest, belonging to the loftiest summits,
stream perfectly free all the way across intervening notches and passes
from peak to peak, while others overlap and partly hide each other. And
consider how keenly every particle of this wondrous cloth of snow is
flashing out jets of light. These are the main features of the
beautiful and terrible picture as seen from the forest window; and it
would still be surpassingly glorious were the fore- and middle-grounds
obliterated altogether, leaving only the black peaks, the white
banners, and the blue sky.
[Illustration: KOLANA ROCK, HETCH-HETCHY VALLEY]
Glancing now in a general way at the formation of snow-banners, we find
that the main causes of the wondrous beauty and perfection of those we
have been contemplating were the favorable direction and great force of
the wind, the abundance of snow-dust, and the peculiar conformation of
the slopes of the peaks. It is essential not only that the wind should
move with great velocity and steadiness to supply a sufficiently
copious and continuous stream of snow-dust, but that it should come
from the north. No perfect banner is ever hung on the Sierra peaks by a
south wind. Had the gale that day blown from the south, leaving other
conditions unchanged, only a dull, confused, fog-like drift would have
been produced; for the snow, instead of being spouted up over the tops
of the peaks in concentrated currents to be drawn out as streamers,
would have been shed off around the sides, and piled down into the
glacier wombs. The cause of the concentrated action of the north wind
is found in the peculiar form of the north sides of the peaks, where
the amphitheaters of the residual glaciers are. In general the south
sides are convex and irregular, while the north sides are concave both
in their vertical and horizontal sections; the wind in ascending these
curves converges toward the summits, carrying the snow in concentrating
currents with it, shooting it almost straight up into the air above the
peaks, from which it is then carried away in a horizontal direction.
This difference in form between the north and south sides of the peaks
was almost wholly produced by the difference in the kind and quantity
of the glaciation to which they have been subjected, the north sides
having been hollowed by residual shadow-glaciers of a form that never
existed on the sun-beaten sides.
It appears, therefore, that shadows in great part determine not only
the forms of lofty icy mountains, but also those of the snow-banners
that the wild winds hang on them.