Zervreila

With the fresh snow and storm force wind, extensive wind slabs form in the north and in Valais. The large amount of new and drifted snow is prone to triggering. Naturally triggered avalanches are to be expected. These can penetrate deeper layers of the snowpack and become very large, especially on the northern Alpine ridge and in Valais.

Slightly less snow falls in Ticino and Grisons. In these regions, new and drifted snow overlay an unstable old snowpack with pronounced weak layers. Naturally triggered avalanches are also to be expected here, which are likely to be mostly medium and large in size. Avalanches can very easily be triggered by human activity, even from larger distances.

During the night, a little snow fell in the north down to low altitudes. During the day it was quite sunny in the Alps. In the afternoon, clouds gathered from the west.

Fresh snow

From Saturday afternoon to Sunday afternoon:

• North of a line between the Rhône and the Rhine: 10 to 20 cm
• Elsewhere: a widespread 5 to 10 cm, dry in the south

Temperature

At midday at 2000 m, between -7 °C in the north and -2 °C in the south

Wind

• Moderate to strong northerly wind at high altitudes and in the south
• The wind shifted to a westerly in the afternoon and became increasingly moderate to strong in the north

There will be heavy snowfall, mainly in the north and Valais. It will remain dry only in the far south. The snowfall level will rise temporarily to 1500 m in the northwest overnight to Monday and will be around 1000 m during the day. Particularly in Grisons, precipitation amounts are uncertain.

Fresh snow

From Sunday evening to Monday afternoon above approximately 1800 m and in the Jura on the highest peaks:

• Northern Alpine ridge, Valais: 50 to 70 cm, locally up to 80 cm on the northern Alpine ridge and in westernmost Lower Valais
• Western Jura, remaining northern flank of the Alps, remaining parts of northern Grisons, northern Lower Engadine: 30 to 50 cm
• Eastern Jura, northern Ticino, central Grisons, rest of Engadine, Val Müstair: 15 to 30 cm
• Elsewhere less, and mostly dry in Sotto Ceneri

Temperature

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

Wind

There will be westerly to northwesterly winds:

• Strong to storm force in the north and in Valais
• Moderate to strong in Grisons and Ticino

On Tuesday, another 30 to 50 cm of snow will fall on the northern Alpine ridge, in Lower Valais, Prättigau, Silvretta and Samnaun, with less expected elsewhere. In the far south, it will be dry and quite sunny. The snowfall level will be at low altitude. Winds will be strong to storm force from westerly to northwesterly directions.

The forecast for Wednesday is still uncertain. Some snow is expected to fall in the north and west overnight to Wednesday. During the day it will be dry and quite sunny, especially in the south. There will continue to be strong westerly winds at high altitudes.

On Tuesday, the avalanche danger will increase further but still remain within the current danger level 4 (high). Apart from the southern valleys, danger level 4 has also been reached in the rest of Grisons. Very large naturally triggered avalanches are to be expected, especially in western and northern Valais. Very large avalanches are also possible along the rest of the northern Alpine ridge and in the rest of Valais. In the affected areas of Grisons, many medium and large avalanches are to be expected due to the weak but thin snowpack. The avalanche situation is critical.

With the end of the intense precipitation on Tuesday evening, naturally triggered avalanche activity will be appreciably reduced. The avalanche danger will decrease slightly on Wednesday, but will remain high.