südliches Urseren

Considerable avalanche danger will be encountered in some regions

Considerable avalanche danger will be encountered in some regions

Weak layers exist in the bottom section of the snowpack, especially on steep north facing slopes above approximately 2400 m, as well as on steep south facing slopes above approximately 2800 m. Single persons can release avalanches in some places, including dangerously large ones. In addition the wind slabs of the last few days are prone to triggering in some locations. They are to be avoided as far as possible. Backcountry touring and other off-piste activities call for experience in the assessment of avalanche danger. In particular on steep south facing slopes wet snow slides and avalanches are possible.

The snowpack shows striking effects of rainfall and wind from this last week. It is thoroughly wet up to high altitudes. At very least the uppermost layers of the snowpack are moist on the northern flank of the Alps up to approximately 3000 m, and in southern regions up to approximately 2600 m; at higher altitudes these layers are dry. During nights of clear skies a crust forms on the surface which is often breakable, i.e. not capable of bearing loads. The crusts subsequently soften up during the course of the day on steep sunny slopes. On the northern flank of the Alps, triggerings of slab avalanches which fracture down to deeper layers of the snowpack are unlikely. From central Valais over the northern Ticino as far as Grisons, deep layers inside the snowpack are weak and, in some places, prone to triggering.

In the mountains it was sunny and extremely mild for this juncture of the season. Fresh snow: - Temperature: At midday at 2000 m, between +9 °C in the northern regions and +11 °C in the southern regions. Wind: Winds were westerly, blowing predominantly at light to moderate strength. It is expected to remain sunny and, for this juncture of the season, extremely mild. Fresh snow: - Temperature: At midday at 2000 m, between +10 °C in the western and the southern regions and +8 °C in the eastern regions. Wind: Winds will be northwesterly, - blowing at moderate strength at high altitudes until the morning of New Year's Day, in the other regions of Switzerland blowing at light strength; - during the afternoon winds will generally be light.

Sunday: During the night on January 1st, skies will be clear and in the morning hours it will be sunny and mild in the mountains. Subsequently, cloud cover will move in from the northwest. In the southern regions it will remain predominantly sunny until evening. The westerly winds will intensify and be blowing increasingly at moderate to strong velocity, in the southern regions at light to moderate strength. The avalanche danger levels will decrease. During the course of the day, wet-snow slides and wet-snow avalanches are possible on steep sunny slopes. Monday: In the northern regions, it will be variably cloudy to heavily overcast, in the southern regions and towards central Grisons, it will be quite sunny. In the northern regions, intermittent light precipitation is possible. The westerly winds will be blowing at strong velocity in the northern regions and at high altitudes in general. Temperatures are expected to drop somewhat. The snowfall level will lie at 1800 m. Avalanche danger levels are not expected to change significantly.