Waadtländer Voralpen

Snowpack

With fresh snow and lots of wind, first from the west to southwest and then from the west to northwest, the last few days have seen widespread snowdrift accumulations form. Some of these are prone to triggering, and some of them were covered with fresh snow by the time snow stopped falling on Saturday and are therefore difficult to spot.

The structure of the old snowpack varies greatly from region to region:

• south of a line from the Rhône to the Rhine, at high altitude the snowpack contains pronounced weak layers in which avalanches can be triggered in places, sometimes right down to ground level.
• these weak layers are also present on the central part of the southern flank of the Alps, as well as in Val Bregaglia and Val Poschiavo, but are very thin and thus in the terrain roughness range. In these southerly regions old snow therefore tends to be unproblematic, except on north-facing slopes above approximately 2600 m.
• north of a line from the Rhône to the Rhine and in the extreme west of Lower Valais, the snowpack structure is more favourable. Avalanches starting in weak layers in old snow are only possible in isolated cases. The snowpack is very strongly affected by the wind.

Weather forecast to Sunday

It will be mostly sunny in the mountains.

Fresh snow

-

Temperature

At midday at 2000 m, between -7 °C in the west, -3 °C in the south and -11 °C in the east

Wind

• increasingly strong north-easterly at high altitudes
• storm force Bise wind in the Jura, moderate to strong Bise wind along the Prealps

Weather review for Saturday

Some snow was still falling in the north at midday. The snowfall level rose to 1500 m in the west on Friday evening and then dropped back to below 1000 m. In Ticino and Grisons, snowfall ended during the night and it was quite sunny during the day.

Fresh snow

From Friday afternoon to midday on Saturday:

• northern flank of the Alps from the Bernese Oberland to the Glarus Alps: 10 to 20 cm
• otherwise a widespread 5 to 10 cm, with fewer centimetres or dry conditions in the southeast

The last 5 days have therefore seen the following totals:

• extreme west of Lower Valais: 60 to 80 cm
• Vaud and Fribourg Alps, Valais, northern and central Ticino as well as the Upper Engadine, Moesano, Val Bregaglia and Val Poschiavo: 40 to 60 cm
• otherwise a widespread 20 to 40 cm, with less in the Jura

Temperature

At midday at 2000 m, between -3 °C in the southwest and -9 °C in the northeast

Wind

Moderate to strong northwesterly during the night, mostly moderate during the day

Outlook

Monday and Tuesday will be mostly sunny. Moderate to strong northeasterly winds at high altitudes, Bise wind in the north until Monday evening. It will become milder again, with the zero-degree level increasing to around 2000 m on Monday and 2500 m on Tuesday.

Avalanche danger will decrease, but only slowly in the areas with persistent weak layers.