Zervreila

Tuesday’s strong to storm-force southerly winds have formed widespread snowdrift accumulations. Ridgelines have often been blown away. In the south, the fresh snow was additionally deposited on top of a weak snowpack. Fresh snow and snowdrift accumulations are often lying on an unfavourable old snow surface of faceted crystals or snow-covered surface hoar and are easily triggered in many places.

There are pronounced weak layers in the snowpack in southern Valais, Ticino and Grisons. 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.

Snow fell down to low altitudes on the Main Alpine Ridge and south of there. There were sunny intervals in the west and north.

Fresh snow

From Monday evening to Tuesday afternoon:

• from Val Bregaglia 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 10 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 storm-force southerly; strong foehn wind in the Alpine valleys of the north
• Dropping somewhat in the afternoon

Conditions will often be cloudy on Wednesday and a little snow will fall in the south. The snowfall level will be around 1000 m. There will be brighter intervals in the afternoon in the west.

Fresh snow

Main Alpine Ridge and south of there: a few centimetres;

Temperature

At midday at 2000 m, between -1°C in the north and -5°C in the south

Wind

Light in the south, otherwise moderate from southerly directions

Thursday

Thursday will be very sunny. Winds will be light to moderate, strengthening from the south in the evening.

Avalanche risk will decrease somewhat in all regions. In southern Valais, Ticino and Grisons, however, it will decrease only very slowly due to the distinct and persistent weak layers.

Friday

Precipitation will set in from the west overnight to Friday. During the day, conditions will be very cloudy and there will be occasional precipitation, falling as snow above approximately 1200 m. Around 20 to 30 cm will fall in the extreme west of Lower Valais. The wind will increasingly become a moderate southwesterly.

Avalanche risk will increase in the west with the fresh snow, but will otherwise not change significantly.