Zervreila

• Westernmost Lower Valais, northern Valais, Vaud Alps: the considerable amount of new and drifted snow resulting from the intensive precipitation of the past few days is still prone to triggering in places. This snow lies on an old snowpack whose central section contains weak layers in places. Avalanches may be triggered mainly at transitions from a shallow to a deep snowpack and can still become very large.
• Southern Valais, Ticino, Grisons: the old snowpack is very weak and contains distinct weak layers in the middle and lower part of the snowpack that are prone to triggering. Avalanches can easily be triggered by human activity in these layers and fractures in the snowpack can propagate over long distances. Avalanches may be very large, especially in southern Valais. Here, the new and drifted snow of the last few days has formed into a very unfavourable combination of layers on top of the weak old snowpack.
• Central and eastern parts of the northern flank of the Alps: there are also weak layers in the old snowpack in these regions. However, avalanches in these layers are less frequent and the main danger comes from the new and drifted snow. Ridgelines and ridges were often cleared by the northwesterly wind. Below approximately 1800 m, the snowpack has been soaked by the sometimes intense rain.
• Prealps: newer snowdrift accumulations lie on a mostly favourable snowpack, but are still prone to triggering in places.

A little snow fell in the north above 1000 m during the night. It was quite sunny in all regions in the late morning, but clouds moved in again from the west in the afternoon.

Fresh snow

From Thursday afternoon to Friday morning above 1400 m:

• Westernmost Lower Valais, northern Alpine ridge from Les Diablerets to the Jungfrau region: 20 to 30 cm
• Jura, rest of Lower Valais, rest of northern Alpine ridge, northern Grisons: 10 to 20 cm
• Elsewhere less, dry along the central southern flank of the Alps

In total, the following amounts of snow have fallen above 2200 m since the onset of precipitation on Tuesday:

• Westernmost Lower Valais, northern Lower Valais: 100 to 140 cm
• Vaud Alps and Fribourg Alps, the rest of Lower Valais, the rest of the northern Alpine ridge west of the Grimsel Pass: 60 to 80 cm
• Remaining western and central parts of the northern flank of the Alps, western Ticino, southern Upper Valais: 30 to 60 cm
• Eastern part of the northern flank of the Alps, northern Grisons, rest of Ticino: 20 to 40 cm, less elsewhere

Temperature

At midday at 2000 m, around -2 °C

Wind

• Strong to storm force from the northwest during the night
• During the day moderate to strong in the west at high altitudes, otherwise light to moderate from the southwest

On Saturday, it will be very cloudy and there will be some precipitation at times; in the south, this will occur during the night, while in the north it will be during the day. The snowfall level in the south will be around 1200 m, while in the north it will drop down to low altitudes.

Fresh snow

From Friday to Saturday evening above 1400 m:

• Simplon area, western Ticino: 5 to 10 cm
• Elsewhere a widespread few centimetres

Temperature

At midday at 2000 m, between -4 °C in the north and -1 °C in the south.

Wind

• Moderate to strong southerly wind during the night, which will then ease and change into a northerly wind
• Increasingly moderate from the northeast during the day

Sunday

On Sunday there will be some more precipitation in the north with sunny spells in the afternoon. Conditions will be quite sunny in the south. There will be a strong northerly wind overnight to Sunday along the Main Alpine Ridge and south of it.

The avalanche danger will continue to decrease in the west, but will not change significantly in the other regions. The northerly winds will lead to the formation of snowdrift accumulations, which will be prone to triggering.

Monday

Overnight to Monday, the precipitation will intensify from the west and two days of heavy snowfall will begin. On the northern flank of the Alps and in Valais, 40 to 60 cm of fresh snow is expected to fall by the evening. The snowfall level will rise temporarily to 1400 m overnight to Monday and fall to low altitudes during the day. The westerly wind will be frequently strong to storm force.

The avalanche danger will increase to high (level 4) in the north on Monday. Naturally triggered avalanches are expected to increase as the day progresses.