Images
of snow bound mountains, deep blue sky, clean and chilled air flash by
as one plans of a holiday. Going up the sky lift as if trying to reach
for the sky, makes a tourist's heart beat excitedly. The trip becomes a
grave tragedy when the snow on the slope decides to move behind the
skiers, wrapping them in a white coffin and burying them. One shudders
to think how ruthless the snow could be.
The Wikipedia says that "An avalanche is a slide of large snow (or rock)
down a mountainside, caused when a buildup of snow released down a
slope, and is one of the major dangers faced in the mountains in winter.
An avalanche is an example of a gravity current consisting of granular
material"
A large avalanche can dislodge and move snow equivalent to 20 football
fields filled with three metres of snow, leaving nothing unturned in its
path.
The suddenness and the swiftness of an avalanche have to be experienced
to visualize how hazardous it could be. Not only snow, but sometimes the
weathered, powdered rock flour produced by the weathering agencies in
snowbound terrains moves with the ferocity of an avalanche. While
searching for fossil remains of marine organisms up the steep valley
slopes of Kurgiakh Chu on Zanskar Mountain in 1975, I had a narrow
escape. After the day's work it was a great fun to slide on the 450
slope formed by the weathered material (scree). The accompanying guide,
Dorje was almost a midget, barely 3' 8" tall. It was getting late in the
evening and we were rushing down to our camp 5000' below in the valley.
We were sliding down in a gully of scree material like skiers. Suddenly
without any warning Dorje lifted me in his short but powerful arms like
a bundle of clothes and dumped me on a small rocky platform on the edge
of the channel. I was hurt and slightly bruised. Before I could
reprimand him, he pointed towards the silent scree avalanche moving
after us which would have engulfed and crushed us.
Descent that day on the cliff on all the fours, minus ropes was quite a
feat and my arms ached for days together.
However, some 243 people were not so lucky in the avalanches that struck
Kashmir in February 2005. For them it was a mass burial in a white
coffin. The avalanche was accompanied by high winds. So powerful was the
avalanche that 305 people remained stuck inside the Jawahar Tunnel, the
entry to Kashmir- the heaven on earth. Continuous snowfall was
responsible for the mishap. India Meteorology Department's (IMD)
reported snowfall up to two meters in the higher reaches of the Pir
Panjal range during 16-20th February, 2005. Crops, plantations and some
10,000 houses in Anantnag, Doda, Pulwama and Poonch suffered extensive
damage because of the sudden heavy snowfall.
Swiftness of this avalanche can be imagined from the fact that 300
search and rescue personnel deployed in Banihal Tunnel area had to take
shelter inside the tunnel.
Avalanches have been studied in great detail, all over the world.
However, they remain one of the most unpredictable hazards. Apparently
calm mass of snow starts sliding down for no reason. Of course reasons
are there, but everyone can not be an expert in the science of
predicting avalanches. However, knowing a bit about them can be helpful
in terms of saving lives.
Anatomy of an avalanche
An avalanche has three main parts. The starting zone, that is generally
high up on the mountain slope. It is this point where the snow gathers
maximum. It is this point where the snow mass breaks off from the
accumulated snow. In case of the avalanche that struck J&K in 2005, the
higher reaches of the Pir Panjal range above the tunnel were the
starting zone.
The next part of the avalanche is the channel or the path that the
avalanche follows. While the avalanche hurtles down the path it almost
'shaves off' the slope and leaves behind a trail bereft of trees.
The run-out zone is the terminal part where the snow along with the
debris picked en route is deposited. After traveling through the
restricted 'chute' or the track the avalanche material on approaching
the run-out zone just fans out. Compared to earlier two parts this zone
is flatter. It is human weakness to seek flat ground for dwellings. Thus
a habitation developed on the run-out zone has all the probability of
burial under the avalanche.
Snow avalanches account for a considerable proportion of the earth's
present mass movement activity. The higher reaches of the Himalayas in
J&K, Himachal Pradesh and Uttaranchal remain under snow cover. In these
areas thousands of avalanches occur. Thousands of tons of ice is moved
by these avalanches that involve vertical displacements of over 1500 m.
High mountain peaks like the Everest, Lhotse and Nuptse face frequent
avalanches. These look spectacular. They are not dreaded by the viewers
from safe distances because they do not affect the habitations. It is
the avalanches near settlements that are feared maximum. Fir example,
villages like Upper Munda and Lower Munda on Banihal-Kazigund section of
the road from Jammu to Srinagar and the habitation at Kazigund itself
are the places most affected by avalanches. Unfortunately the upper
reaches of Kazigund fall in the run out zone of the avalanche.
Once upon a time Kalpa the old headquarters of Kinnaur district, H.P.
was constantly battered by avalanches. It was prudent on part of the
government to have shifted the headquarters to Peo, a comparatively
safer place.
Avalanches are capable of wiping off the villages. Tunda, a small
village in Ladakh was swept off by an avalanche in 1838.
In their wake the avalanches apart from snow carry lots of boulders,
lose rocks, even tree trunks and dump them in the run out zone. If it
happens to be the course of a river a blockade takes place. Spiti River
valley faced such blockades in 1978. The flash floods that follow such
blockades become a nightmare for the habitats downstream.
Worst part about an avalanche is that it might occur far away from the
habitation yet it might take the residents by surprise and leave a trail
of tragedy.
We will read more about the causes of avalanches and safeguards against
them in the forthcoming issues.
October 1, 2006
Image "Trek obstructed by an avalanche"
by VK Joshi
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Images
of snow bound mountains, deep blue sky, clean and chilled air flash by
as one plans of a holiday. Going up the sky lift as if trying to reach
for the sky, makes a tourist's heart beat excitedly. The trip becomes a
grave tragedy when the snow on the slope decides to move behind the
skiers, wrapping them in a white coffin and burying them. One shudders
to think how ruthless the snow could be. 
