Wind slab
- Above 1,800 m
Snowpack
The large amount of new snow that has fallen in the last few days is lying in many places on an unfavourable, faceted old snow surface. In the south, on the eastern part of the Main Alpine Ridge, in the inneralpine regions of central Grisons and in the Engadine, often the entire old snowpack is faceted and loose, especially on shady slopes protected from the wind. In such places, avalanches can take the entire snowpack with them. The many naturally triggered and artificially triggered avalanches over the last two days, often large in size, confirm the critical situation.
North of a line from the Rhône to the Rhine and in the extreme west of the Lower Valais, the middle part of the snowpack is often well consolidated, and in these regions avalanches are to be expected mainly within the new and drifted snow layers and at the transition to old snowpack. Fractures in the deep layers of the old snowpack are less probable here.
With strong southerly winds at times, wind slabs, some of them prone to triggering, will develop adjacent to ridgelines and generally in the regions exposed to the foehn wind.
Weather forecast to Thursday
On Thursday, a little snow will fall in the south above approximately 1000 m. From Upper Valais via central and eastern Switzerland to northern and central Grisons, there will be brighter spells with foehn winds. Elsewhere it will be mostly cloudy.
Fresh snow
From Wednesday evening to Thursday afternoon above approximately 1400 m:
Temperature
At midday at 2000 m, between -4 °C in the south and -1 °C in the north.
Wind
Weather review for Wednesday
Some snow fell during the night, especially in the west above approximately 1000 m. It was mostly sunny during the day.
Fresh snow
From Tuesday evening to Wednesday morning above 1400 m:
Temperature
At midday at 2000 m, around -4 °C.
Wind
Outlook
On Friday, there will be a little snow initially in the north and later also in the south. The snowfall level will be 1000 m. More widespread brighter spells are possible in the inneralpine regions. On Saturday, a little snow will fall in the south above approximately 1000 m. North of the Main Alpine Ridge, it will be mostly sunny in the mountains and cloudy along the Prealps.
The danger of dry avalanches will decrease, but only slowly, especially in the south and in Grisons. In these regions, the conditions remain critical for off-piste snow sports due to the weak snowpack.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)