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During winter and spring, snow is transformed by the sun and the wind. The snowpack changes. To advance in the best and safest conditions, it is better to know how to read the snow. The Mountain Guides can give you all the information you need to know.
During snowfall and in the days that follow,the wind transports the snow. Systematically, it will accumulate on the leeward side (opposite side to the prevailing wind) of mountain passes and high ridges, as well as on slopes where there is rock or ground movement.
Take a good look around you: small indicators help you guess the direction of the prevailing wind. Therefore, you can figure out the slopes where snow will accumulate as snowdrifts and, below these, possible wind slabs.
Sintering of the snow is one of these indicators. Small beads form on the surface of the snow layer. They have a sharp or stepped side. This side is the one in the direction of the wind.
Another indicator: the small trees on the subalpine level. They fight the natural elements to survive. Conifers adapt particularly well and develop a flagbearing appearance by letting their branches die that face the direction of the wind. The side where the tree’s branches will grow horizontally and often at ground level is called the leeward side.
Every ridge or marked relief implies that a snowdrift has formed. It will be more or less higher, more or less overhanging. It's extremely dangerous to go over it. When walking on the ridges, always choose the windy side where there isn't much snow. In any case, keep a few metres back from the edge of the snowdrift. They are nearly always considerably overhanging.
The mountain level (up to 1,800 m altitude on average) is characterised by the presence ofshrubs (willows, alders, etc.) that bow under the weight of the snow from the first flurry and often remain captive to it for the entire season.
Flurry after flurry, they can be completely covered. They form bumps under the snow. Their presence is sometimes shown by a few twigs. They should be avoided so you don’t sink abruptly into an air pocket made by their branches.
Even under the snow, rocks catch the sun's rays and release them. This makes the snow melt to ground level, creating a melted pocket around the rock. It can surprise you and make you fall. So it's best to avoid rocks. The majority are given away by a bump or snow that looks frozen or refrozen.
On rocky landscapes (blind, moraine, etc.), generally the snow doesn't cover all the rocks. When advancing through these surroundings, the hiker must always keep in mind that an air pocket, sometimes deep, could be covered by a “snow bridge”, more or less solid. If the weather has been cold for several days, you can assume that the bridge will hold.
In any event, it's better to avoid suspected snow bridges. If there is no other alternative then test it with a pole, cross slowly one by one, walking softly! The most cautious thing to do off piste (snowshoeing, cross-country cruising or ski touring) is to go with mountain guides. They are trained in snow conditions and know how to detect the most common risks. They will share their assessment and thinking to justify their decision to change route or objective. You will learn to be cautious in all situations.
If you are heading out alone, equip yourself with the indispensable safety trio:
- Avalanche Transceiver- Probe- Shovel
Be aware there is no point being equipped if you don't know how to use it! You can't improvise when it comes to using an avalanche transceiver. Good preparation ahead of your trip is essential so don't hesitate to speak to a professional before heading out alone.