Zervreila

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

In southern Valais, Ticino and Grisons, there are distinct weak layers deeper in the old snowpack. The number of avalanches triggered by human activity has decreased over the course of the week, but many whumpfing sounds are still being reported. 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.

Conditions were often cloudy on Wednesday and a little snow fell in the south. There were brighter intervals in the afternoon in the west.

Fresh snow

From Monday evening to Wednesday evening, above approximately 1000 m:

• Main Alpine Ridge from the Simplon Pass to the Bernina region and south of there: 20 to 30 cm
• rest of the Main Alpine Ridge and rest of the Engadine: 5 to 15 cm; elsewhere less or dry.

Temperature

At midday at 2000 m, between -3°C in the north and -5°C in the south

Wind

From southerly directions:

• moderate to strong overnight
• subsiding during the day, mostly light in the afternoon

Overnight to Thursday, some snow will continue to fall in the south and east above approximately 1000 m. Conditions will be very sunny everywhere during the day, with clouds gathering from the south-west in the afternoon.

Fresh snow

A few centimetres on the central part of the Main Alpine Ridge and to the south and in central Grisons and the Engadine

Temperature

At midday at 2000 m, around -1°C

Wind

• Light to moderate from westerly directions
• Foehn winds will rise in the Alpine valleys of the north in the afternoon.

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 1300 m. Around 20 to 30 cm will fall in the extreme west of Lower Valais. There will be brighter intervals in the south during the day. 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.

Saturday

Precipitation will come to an end in the north overnight to Saturday. Conditions will be very sunny with light winds during the day.

Avalanche risk will decrease a little but only very slowly in southern Valais, Ticino and Grisons due to the distinct and persistent weak layers.