Weakly bonded old snow and gliding snow require caution
Edition: 15.12.2021, 17:00 / Next update: 16.12.2021, 18:00
Snowpack
Weak layers exist near the base of the snowpack in particular on west, north and east facing slopes above approximately 2200 m. In western Lower Valais and on the northern flank of the Alps, these near-ground layers are mostly embedded so deep that the probability of avalanches being released by people is rather small. From central Valais through Ticino to Grisons and generally in places with shallow snow cover, the bonding of the snowpack is least favourable, and people can still release avalanches in the old snowpack.
Gliding avalanche activity is high. Further gliding avalanches originating on steep grassy slopes that have retained the snow thus far are to be expected in the coming days as well. They can be released at any time of day or night. In the western and northern regions with a lot of snow, these can reach a large size in some cases.
On steep south facing slopes, the surface of the snowpack will become moist because of its exposure to warming and radiation during the day. Here, the clear skies on Wednesday night will give rise to a melt-freeze crust on the surface of the snowpack.
Observed weather on Wednesday, 15.12.2021
On Wednesday in the mountains it was fairly sunny, apart from some cirrostratus cloud.
Fresh snow
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Temperature
  • At midday at 2000 m: between +6 °C in the west and south, and +2 °C in the east
  • The zero degree level was above approximately 3000 m in the west and between approximately 2200 and 2500 m in the east.
Wind
Light to moderate from the north to northeast
Weather forecast through Thursday, 16.12.2021
After a clear night, it will be sunny in the mountains.
Fresh snow
-
Temperature
  • At midday at 2000 m: between +7 °C in the west and +3 °C in the east
  • The zero degree level will slowly drop back below 3000 m in the west, but remain between approximately 2200 and 2500 m in the east
Wind
  • At 2000 m light to moderate from the northeast, in Ticino a moderate north foehn
  • At 3000 m moderate to strong from the northeast
Outlook through Saturday, 18.12.2021
In the mountains each of the coming days will be mostly sunny and mild. The wind will be mostly light to moderate from the north to east. The bise wind will strengthen on Saturday.
The danger of dry avalanches will continue to decrease slowly. In particular in the inneralpine regions where there is no conspicuous avalanche problem, avalanches can still be released by people. The danger of gliding avalanches will persist. The danger of moist avalanches will increase during each of the coming days on very steep sunny slopes.