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Die Natur als Erfindung des Menschen
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Avalanches

deutschLawinen

The word avalanche has its origin in the latin words labi = to glide and labina = landslip.
In general avalanches are masses of snow, which are sliding down the mountains.They are found in the high mountains like the Alps,they are unusual in the secondary chain of mountains.

There are different forms of avalanches: Ice-avalanches, avalanches of loose snow,avalanches of dry snow, dust avalanches, avalanches of wet snow and avalanches of earth
The Ice-avalanche:
This form consists of ice-blocks,which are falling down.The avalanche exists only in the high mountains.The skiing-area at the end of the glacierplateau at the Grand Combin is notorious for ice avalanches for example.
Ice-avalanches come into being at hanging glaciers or when glaciers break.On the one hand ice falls off in the form of loose ice-crumbs because the sunlight warms it up.
On the other hand large masses of ice of a hanging glacier break off in various frequencies.This variant of an ice-avalanche often causes accidents, because you can’t appraise it.The glacier moves night and day.

The avalanche of loose snow:
This avalanche is composed of unbound loose snow. In general it has little masses,but it glides
down at a slope of fifty degrees.These avalanches of loose snow can mutate to a dust avalanche,when the mass is big enough.

The dust avalanche:
It is built of powdery snow,when the temperature is low enough.Catastrophes with avaanches are the results of these dust avalanches.For example the catastrophy in St.Anton in winter 1987/1988.
This form is relatively unusual.
The dust avalanche can obtain a speed of a several hundred kilometers per hour.This avalanche
is a mixture of air and snow and fills the lungs until choking.There is no chance to survive.

The avalanche of dry snow:
It is built of unbound dry snow and it is the result of the ski-runners.

The opposite to this avalanche is the avalanche of wet snow:
This form comes into being after the exposure of sunlight and it ends with the death of the ski-runners.

The avalanche of earth:
This avalanche is a special form of the avalanche of wet snow.It is only found at declivities of
gras or at soils for forest growth.
These avalanches are very powerful and there is no chance to survive.
The extent and the position of the ski-runner is important for the occurrence of an avalanche.
The mass and the length are important factors,too.
The more powerful and longer the avalanche is,the lower is the chance to survive.
In smaller avalanches,which are caused by themselves,you often have a chance to survive.
When there is a bigger avalanche you can only survive when you can move your head and at least one arm.

The redemption of an avalanche
On the one hand there are avalanches,which are spontaneously caused by themselves.On the other hand avalanches are often caused by ski-runners.
Factors of the formation of avalanches are: temperature,mass and kind of snow,the steepness of the declivity and the ability to glide on the underground.
If the temperature is lower than eight degrees under zero,the powdery snow will be saved,but the dangerous situation will exist,too.Great masses of new and cold snow lay on a layer of warm and old snow.
If the conditions are bad,an avalanche can be caused,if there are only fifteen centimeters of snow.If the conditions are good,an avalanche can be caused,if there are forty centimeters of snow.
The critical steepnes of the declivity comes to thirty degrees at the steepest place.
The underground:
Ideal to glide on is grassland and a declivity with forest growth and leaves.Only a tight forest can
prevent the avalanche.
Now some safety orders:
- take an equipment for searching for human beings under the snow with you
- consider the differences of temperature
- and please don’t leave the route ( loipe )
deutschLawinen



obenAutoren: Klasse 11-3 (97/98), teacher Christine Hartmann, Web: Mathias Schönmann  Datum: Juli 98. Last update am 11. März 2000
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