Waadtländer Voralpen

As a consequence of new snow and wind a high avalanche danger will be encountered over a wide area.

Snowpack

With rain to high altitudes and snowfall and wind above, avalanches, some of them large, occurred in Valais in particular, but also elsewhere on the northern flank of the Alps. At high altitudes, there is about twice as much snow in many areas as there normally is at the beginning of December. The snowpack has a favourable structure, apart from thin weak layers of angular crystals deep in the snowpack in the area of older rain crusts. With all the new fallen snow and heavy rain, these weak layers may be reactivated. In the south, the snow depths are below average and the weak layers are therefore closer to the surface. Especially there, the older weak layers may be released, including by people in some cases. In all regions and in all aspects, more gliding avalanches are to be expected below approximately 2400 m on slippery ground.

Weather forecast through Tuesday, 12.12.2023

It will be very cloudy with precipitation, sometimes heavy in the west and north. The snowfall level will initially drop slightly and then rise again to 2200 m in the west and 1800 m in the southeast.

Fresh snow

Until Tuesday afternoon, the following amounts of fresh snow are anticipated above approximately 2500 m:

• Northern Alpine Ridge and extreme west of Lower Valais: 20 to 30 cm, and up to 40 cm along the border with France and from the eastern Bernese Oberland to Central Switzerland;
• rest of Valais and northern Prättigau: 10 to 20 cm;
• less elsewhere.

In the Prealps and Jura, all the precipitation will fall as rain.

Temperature

At midday at 2000 m, between +3 °C in the northwest and +1 °C in the southeast.

Wind

Moderate to strong westerly winds will blow on the northern flank of the Alps and generally at high altitudes.

Observed weather review Monday, 11.12.2023

It was very cloudy with precipitation. This was heavy during the day in the west and north. The snowfall level in the north and far west was between 2200 and 2400 m, and elsewhere between 1400 and 2000 m.

Fresh snow

From Sunday afternoon to Monday afternoon, the following amounts of fresh snow fell above approximately 2600 m:

• Lower Valais, Northern Alpine Ridge and central part of the Main Alpine Ridge: 30 to 50 cm;
• other parts of Valais, Prättigau to Samnaun, as well as the highest peaks north of the Northern Alpine Ridge: 20 to 30 cm;
• less elsewhere.

Temperature

At middle at 2000 m, between +3 °C in the northwest and around +1 °C in the southeast.

Wind

The westerly wind was:

• strong to storm force in western and northern areas;
• in Grisons and Ticino, mostly moderate and locally strong.

Outlook through Thursday, 14.12.2023

It will remain very cloudy with precipitation. Most precipitation will fall in the west on Wednesday with moderate to strong westerly winds, then mainly in the north on Thursday with northwesterly winds. The snowfall level will drop rapidly from 1800 m to around 1000 to 1400 m. From Tuesday afternoon to Thursday afternoon, 40 to 60 cm of snow will fall on the Northern Alpine Ridge and in Lower Valais; 20 to 40 cm in the other regions of the northern flank of the Alps, Valais and northern Grisons and in the western Jura; less elsewhere. The avalanche danger will decrease slightly on Wednesday, except in the far west. It will increase again slightly in the north on Thursday. In the other regions of Grisons and in the south, the avalanche danger will not change significantly.