Grimselpass

Increase in avalanche danger in the west. In the south a considerable avalanche danger will persist.

In some places avalanches can be triggered in the weakly bonded old snow and reach a dangerous size. These avalanche prone locations are difficult to recognise. Caution is to be exercised in particular at transitions from a shallow to a deep snowpack. In addition avalanche prone wind slabs will form adjacent to ridgelines and in gullies and bowls and in the high Alpine regions. Backcountry touring calls for experience and a certain restraint.

In particular on steep south facing slopes individual gliding avalanches are possible below approximately 2000 m.

Snowpack At elevated altitudes there is less snow than usual on the ground for this juncture of the season. At 2500 m the snow depth from the Simplon region over Goms into the Gotthard region and in the central sector of the southern flank of the Alps amounts to approximately 80 cm, in the other regions of Switzerland 40 to 60 cm over widespread areas. In the Lower Engadine and in the central Valais there is even less snow on the ground. As a consequence of fresh fallen snow and moderate-to-strong velocity winds, snowdrift accumulations are being generated. These drifted snow masses are being deposited in some places on top of a loose snowpack surface or atop surface hoar. They are prone to triggering. Particularly on shady slopes above approximately 2200 to 2400 m there are weak, expansively metamorphosed (faceted) layers inside the snowpack over widespread areas. Inside these layers, avalanches can be triggered. The weak old snowpack on the Main Alpine Ridge from the Matterhorn into the Bernina region is sufficiently deep and cohesive that dangerously large-sized avalanches can be generated. Observed weather review Thursday, 08.12.2022 Nocturnal skies were clear and thereafter it was sunny in the mountains during the daytime. Fresh snow - Temperature At midday at 2000 m, temperatures lay between -3 °C in the western regions and -5 °C in the eastern regions. Wind On the northern flank of the Alps and in the Valais, winds were blowing predominantly at moderate strength, in the remaining regions of Switzerland mostly at light strength. Weather forecast through Friday, 09.12.2022 On Thursday evening, snowfall is expected to set in from the west. During the night, snowfall is anticipated to fall down to low lying areas. During the daytime on Friday, skies will be heavily overcast, intermittent snowfall is anticipated. Fresh snow Between Thursday afternoon and Friday afternoon, the following amounts of fresh snow are expected above 1500 m:

• Lower Valais along the French border as well as on the northern Alpine Ridge west of the Wildstrubel: 15 to 30 cm;
• Fribourg and Vaud Alps, Main Alpine Ridge between Val Ferret and Matterhorn, as well as from Val Bregaglia into the Bernina region: 10 to 20 cm;
• in the remaining regions of Switzerland, up to 10 cm.

Temperature At midday at 2000 m, in the northern regions -2 °C, and in the southern regions -4 °C. Wind

• During the night in the northern regions and at elevated altitudes, winds will be blowing at moderate to strong velocity from southwesterly to westerly directions.
• In the northern regions on Friday morning, moderate-velocity foehn wind influence is anticipated for a brief time.

Outlook through Sunday, 11.12.2022 Saturday On the northern flank of the Alps and in northern and central Grisons, a small amount of snowfall is anticipated. In the other regions of Switzerland, skies will be heavily overcast, but it is expected to remain dry. Avalanche danger levels are not expected to change significantly. Sunday During Saturday night in the northern regions, a small amount of snowfall is possible. During the daytime hours on Sunday, skies will brighten up from the west. In the southern regions it will be sunny. Avalanche danger levels will incrementally decrease in the northern regions. On the southern flank of the Alps, trigger-sensitive snowdrift accumulations are expected to form as a consequence of strong-velocity northerly winds.