Gruyère

Snowpack

Widespread snowdrift accumulations have formed over the past week, initially with fresh snow and winds from the west to southwest, then from the west to northwest and at the weekend with northeasterly and Bise winds. Some of the snowdrift accumulations are prone to triggering.

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.
• in central and southern Ticino, as well as in Val Bregaglia and Val Poschiavo, these weak layers are present, but are very thin and therefore in the range of terrain roughness. 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 Monday

Conditions will be mostly sunny in the mountains.

Fresh snow

-

Temperature

rising, at midday at 2000 m between -1 °C in the southwest and -5 °C in the northeast

Wind

• mostly strong at high altitudes, from the northeast during the night and from the east during the day
• moderate to strong Bise wind in the Jura and along the Prealps

Weather review for Sunday

In the mountains, conditions were mostly sunny although there were a few patches of cloud.

Fresh snow

-

Temperature

At midday at 2000 m, between -6 °C in the west, -4 °C in the south and -10 °C in the east

Wind

• moderate to strong from the northeast at high altitudes, storm-force at times on the central part of the main Alpine ridge
• moderate to strong Bise wind in the Jura and along the Prealps

Outlook

Tuesday and Wednesday will be mostly sunny, with moderate to strong northeasterly winds at high altitudes and moderate to strong Bise winds in the north. It will be milder, especially on Tuesday, with a zero-degree level of 2600 m in the west and 2200 m in the east. On Wednesday, this will drop to around 1400 m in the east.

Avalanche danger will decrease, but only slowly in areas with persistent weak layers. These higher temperatures will cause gliding avalanche activity to increase again somewhat in the north and west.