westliche Berner Voralpen

Snowpack

In southern Valais, Ticino and the inneralpine regions of Grisons, there are distinct weak layers in the snowpack. At the weekend, human activity triggered lots of medium and sometimes large avalanches in the weak old snowpack in these regions, often from a distance.

Snowpack structure is somewhat more favourable on the northern flank of the Alps and in northern Valais, but there are weak layers deeper in the snowpack in these regions too. These may still be triggered, especially where there is little snow and at transitions from a deep to shallow snowpack.

During the night to Tuesday, snow will fall on this weak snowpack in the south and naturally triggered avalanches are possible. Snowdrift accumulations will form in many areas with the strong to stormy southwesterly winds. In many places, these will be deposited on an unfavourable surface of faceted crystals or surface hoar. This means that the fresh snowdrift accumulations will often be easily triggerable.

Weather forecast to Tuesday

Snow will fall down to low altitudes on the Main Alpine Ridge and south of there. Otherwise, it will be partly sunny with some precipitation at times.

Fresh snow

From Monday evening to Tuesday afternoon:

• Main Alpine Ridge from the Lukmanier Pass to the Bernina Pass: 15 to 25 cm
• Central part of the southern flank of the Alps: 10 to 20 cm
• rest of the Main Alpine Ridge: 5 to 15 cm; elsewhere: less or dry.

Temperature

At midday at 2000 m, between -2 °C in the north and -5 °C in the south

Wind

• Strong to stormy southwesterly wind during the night, strong to stormy foehn wind in the Alpine valleys of the north
• Subsiding somewhat during the day

Weather review for Monday

It was mostly sunny in the north and very cloudy in the south.

Fresh snow

-

Temperature

At midday at 2000 m, between 0 °C in the north and -6 °C in the south

Wind

• Increasingly moderate to strong southwesterly winds
• A moderate to strong foehn wind blew in the Alpine valleys of the north.

Outlook to Thursday

On Wednesday it will often be cloudy and a little snow will fall in the south. On Thursday it will be quite sunny in the north, but only partly sunny in the south. There will be a light to moderate southerly wind on both days.

The avalanche danger will decrease somewhat in all regions. However, it will decrease only very slowly in southern Valais, Ticino and Grisons due to the distinct and persistent weak layers.