rumbling sound is heard which rapidly increases and
seems to draw nearer with appalling intensity of tone.
Presently the white flood comes bounding into sight
over bosses and sheer places, leaping from bench to
bench, spreading and narrowing and throwing off clouds
of whirling dust like the spray of foaming cataracts.
Compared with waterfalls and cascades, avalanches
are short-lived, few of them lasting more than a minute
or two, and the sharp, clashing sounds so common in
falling water are mostly wanting; but in their low
massy thundertones and purple-tinged whiteness, and
in their dress, gait, gestures and general behavior,
they are much alike.
Avalanches
Besides these common after-storm avalanches that are
to be found not only in the Yosemite but in all the
deep, sheer-walled canyon of the Range there are two
other important kinds, which may be called annual
and century avalanches, which still further enrich
the scenery. The only place about the Valley
where one may be sure to see the annual kind is on
the north slope of Clouds’ Rest. They are
composed of heavy, compacted snow, which has been
subjected to frequent alternations of freezing and
thawing. They are developed on canyon and mountain-sides
at an elevation of from nine to ten thousand feet,
where the slopes are inclined at an angle too low
to shed off the dry winter snow, and which accumulates
until the spring thaws sap their foundations and make
them slippery; then away in grand style go the ponderous
icy masses without any fine snow-dust. Those
of Clouds’ Rest descend like thunderbolts for
more than a mile.
The great century avalanches and the kind that mow
wide swaths through the upper forests occur on mountain-sides
about ten or twelve thousand feet high, where under
ordinary weather conditions the snow accumulated from
winter to winter lies at rest for many years, allowing
trees, fifty to a hundred feet high, to grow undisturbed
on the slopes beneath them. On their way down
through the woods they seldom fail to make a perfectly
clean sweep, stripping off the soil as well as the
trees, clearing paths two or three hundred yards wide
from the timber line to the glacier meadows or lakes,
and piling their uprooted trees, head downward, in
rows along the sides of the gaps like lateral moraines.
Scars and broken branches of the trees standing on
the sides of the gaps record the depth of the overwhelming
flood; and when we come to count the annual wood-rings
on the uprooted trees we learn that some of these immense
avalanches occur only once in a century or even at
still wider intervals.
A Ride On An Avalanche
Copyrights
The Yosemite from Project Gutenberg. Public domain.
