Middle Lys Valley

Wind slabs and weakly bonded old snow require caution. As a consequence of new snow and wind the avalanche prone locations will become more prevalent in the evening.

Wind slabs and weakly bonded old snow require caution. As a consequence of new snow and wind the avalanche prone locations will become more prevalent in the evening.

The fresh snow from last week, and especially the wind-blown snow drifts, both soft and hard, cover a thin layer of old snow. Single winter sport participants can release avalanches as before, including medium-sized ones. Mostly they are shallow, caution is to be exercised in particular in gullies and bowls, and behind abrupt changes in the terrain, and on very steep slopes. On very steep shady slopes the avalanches can be triggered in deep layers of the snowpack and reach large size in isolated cases. Slopes that have been little used this winter thus far where weaknesses exist in the old snowpack are especially unfavourable. Isolated whumpfing sounds and shooting cracks when stepping on the snowpack serve as an alarm indicating the danger. Careful route selection and spacing between individuals are recommended. Some snow will fall in the evening. The wind will be moderate to strong. These meteorological conditions will prevent a change towards better conditions.

As a consequence of new snow and a moderate to strong wind from northwesterly directions, wind slabs formed above the tree line. Faceted weak layers exist in the old snowpack in particular on west, north and east facing slopes. As a consequence of solar radiation a crust formed on the surface during the last few days, in particular on very steep south facing slopes. Since Thursday, numerous spontaneous and triggered slab avalanches have been observed, especially in areas bordering Switzerland and France.

The wind will be moderate to strong. Some snow will fall until midday. As a consequence of new snow and a moderate to strong wind from southeasterly directions, further wind slabs will form.