by Adelin (Dec 21, 2005)

Snow crystals arise and develop in clouds in which water droplets can freeze at a temperature below 0°C. Under the action of certain suspended particles of dust, water droplets transform into ice particles. Then the water steam condenses in the form of ice in these suspended particles of dust. So the crystal grows as big as a few millimetres and its shape depends on the temperature in which it develops.

A live material

Snow is a live material. From its accumulation on the ground to its thaw, which feeds mountain streams, snow crystals are transformed by different meteorological parameters like wind, temperature, humidity, sunshine hours, rain…

These metamorphoses are continuous. When the temperature is below 0°c, snow crystals are transformed into granular or angular forms, whose diameter varies from about 0.2 to 2 mm. During the thawing period, the snow temperature is 0°c. The liquid water, present in the snow at that moment, transforms the snow grains into big round grains.

The snow coat

The accumulation of different snow coats, whose characteristics are different, constitutes the snow coat. 

The metamorphoses lead to the forming of a changing coat, dry or humid, soft or cracking. When it contains liquid water, snow is like a paste, more or less fluid.

Avalanches

An avalanche is the quick circulation of a snow mass on a slope.

The “spontaneous” avalanche, also called “natural”, is released by the action of meteorological parameters : abundant snowfalls, cold and wind, great warming especially if it is accompanied by rain.

The “provoked” avalanche, also called “accidental”, is released by the passage of a skier whose excess load is sufficient to break the fragile balance of a snow plate or by pyrotechnicians with the aid of explosives.

An avalanche can be characterised by the quality of snow (dried, humid,…), by the breaking (punctual, linear,…), by its circulation….

Will there be snow in 2030 ?

The increase of the average temperature will entail a total or partial thaw of the snow. So if you want to protect this beautiful nature element, reduce your energy consumption.

If you wish to react to this article, write to the editor.

Jan 18, 2006

I agree with you. If we want to continue to have snow, we must absolutely reduce our CO2 emissions. So we must reduce our petrol consumption and favour the bike or the walk! The global warming which is happening disrupts the whole ecosystem and we must react !! Governments have taken measures to reduce CO2 emissions. But a few countries, in particular the United States, which is the biggest polluter, haven't signed this charter. So we must absolutely react if we still want to ski.

Delphine (Blois, YGTP)