Year: 1875




ABOUT AYALANCHES.


How they start-Rolling and Sliding


.Avalanches-None of them Agreeable
Nfsitants.


Avalanches-in this country generally
spoken of as snow-slides-are oftwo kinds,
the. rolling and the sliding; though the
rolling avalanches often plunge and slide
for considerable distance through the
lower part of their course. The purely
sliding avalanches, or snow-slides. are such
as occur in dry or merely moist snow,
while the


ROLLING AvALANCHES


rake place when the snow Is wet or suffi-
Gently moist to form into balls by rolling.
The ayalanches that occurred in this city
day before yesterday were of the genuine
rolling description-the kind most dread
ea land most destructive in the valleys of
TIE Alps. A very small beginning when
the Snow, is in the proper condition may
END in destructive avalanche. A ball of
snow no larger than mans head, started
high up, on the side of Mount Davidson
day before yesterday, might have swept
away several houses at the foot of the
mountain. The fearful force of the ava
lanche was shown here day before yesier-
!. dssJs, when the first one broke into a house
and killed two men, and the second de-
molished two houses and buried five per-
sons, who were rescued with much diff
Guilty. A further illustration of the ter
rible force and destructive powers of the
avalanche is to be found in the fact that
twenty-eight Cinnamon were killed night
before last by one that fell near Genoa. AS
we have said, small ball of snow started
high up on the slope of Mount David
son would result in a genuine avalanche.
In rolling distance of fifty yards in the
moist snow the small ball of snow would
become four or five feet in diameter, when
it would burst and each piece of it would
an instant after form ball of large size
these in turn would explode as soon as
they had acquired certain weight and
velocity, and moment after there would
be hundreds and thousands of these balls
in motion, all bounding down the steep
side ofthe mountain. While hundreds of
these are exploding or just forming, other
hundreds are of full size and are picking
up rocks, dirt and all manner of rubbish,
which becomes involved in the grand
downward rush. Toward the lower part
of their course the balls become so numer-
Gus that they bound and clash together so
often that they are broken before they ac-
quire any great size, and the whole avail
anche is then a plunging, sliding mass of
snow. The second avalanche which oc-
Cured here day before yesterday, and
which knocked two houses to pieces and
buried five persons, started but few hun
died yards above where the houses stood.
1t started at bunch of rocks which pro-
jected fifteen or twenty feet above the
general surface of the slope of the noun
tain. On these rocks the snow had fallen
and accumulated to the depth of about
three feet, hanging in places as snow is
seen to do on the caves of house. From
one of these rocks fell bunch of snow
which began to roll down the hill and the
result was destructive avalanche.
Doubtless the first avalanche-the one
which came down in the morning, and
which killed two men-started in much
the same way. If there are any who
doubt the correctness of what we have
said about this description of avalanche,
let the doubters ascend Mount Davidson
when the snow shall next be found in
proper condition and start down a few
small balls and we will bet new hat we
get a ffrst-class item out of the expert
ment.


SLIDING AVALANCHES.


Besides the rolling avalanches there are
two other kinds seen in the mountains of
the Pacific Coast, both of which slide from
the start just as snow is seen to slide from
the roof of house. The first of these oc-
ours when foot or more of fresh snow
has fallen upon the frozen surface of a
former snow-snow that is covered with a
smooth. CLASSY crust. Although bad
enough, this species of avalanche is not so
fiercely destructive as are such as occur in
wet snow, but once such an avalanche
starts on the side of a mountain it never
stops until it has reached a valley.


AvALANCHEs IN THE HIGH sIERRAs.


The second kind of sliding avalanche oc-
ours among the higher peaks of the Sier-
ras-far up where there are vast areas of
naked rock. They are fOrmcl of snow
which slides from the face of great slopes
of bare rock. Such avalanches are sure to
occur when the first snow of the season
proves 10 be of the depth of foot or more.
The rocks are then warm and the snow
accumulating upon them melts on the un-
der side, till finally so much water is
formed that the whole mass slides off. Just
as snow is thawed and slides from the roof
of house. These being somewhat wet,
often carry with them great quantities
of rocks, and if they have long run to
make often sweep trees and all before
them before reaching the valleys. We have
had the dismal pleasure of hearing a num-
Der of these fall while lying under COW
ering of about two feet of snow among
the peaks of the mountains high above the
Yosemite Valley. There would first fill
the sir a sort of hissing roar, as though
snow were sliding off thousand-acre
roof, then about from two to four seconds
of deep silence, followed by the tremen-
dOus roar and clatter of the snow and
rocks falling from the brow of the Semi
dome and other great mountain peaks into
the valley below. In the winter of 1859
we heard at least a dozen of these ava
lanches fall into Yosemite Valley in one
night. 1t was the first snow of the sea-
son, and was very good night for ava
lancheS.


How we came to have this avalanche ex-
perience may be explained in single SEN
tence: Fools rush in where angels fear
to tread" About the headwaters of the
Tuolumne River, far up toward Mono
Pass, are to be seen semi-circular walls of
rocks and trees ground to fragments,
which are ten feet in height, and which
have been pushed far out into the deep
valleys. In conclusion, we would remark
that avalanches are good things-tO little
on the upper end of.-VuginiG City En-
serprise.


Effect of Exercise.


1t is found by observation that the effect
af - traipinn - nr tha nQrcicfa0t uSn of