Considerable avalanche danger will be encountered in some regions
Edition: 30.12.2021, 17:00 / Next update: 31.12.2021, 18:00
Snowpack
On the northern flank of the Alps, rain fell up to 2800 m. In the other regions on the main Alpine ridge and to the north, it rained up to approximately 2600 m. In consequence, the snowpack became thoroughly moist up to high altitudes or, in areas close to the snowfall level, at least the near-surface layers of the snowpack became moist. At elevated altitudes, the strong to storm force northwesterly wind transported large quantities of the fresh snow and in some cases the old snow as well.
The warm and moist snow is settling quickly. In addition, with clear night skies, the snow surface will freeze on Thursday night, which will promote the rapid stabilisation. In places where the snowpack remained dry, namely in the high Alpine regions on the northern flank of the Alps and elsewhere above approximately 2600 m, the snowpack is stabilising more slowly. Furthermore, from central Valais through northern Ticino to Grisons, the fresh snow and snow drift accumulations are lying on weakly bonded old snow and remain prone to triggering at elevated altitudes in these regions in particular.
Observed weather on Thursday, 30.12.2021
Thursday morning saw the end of the precipitation period that began on Monday and encompassed all regions on the main Alpine ridge and to the north. During the day, it was quite sunny in central and southern Ticino and in Valais, and it became gradually brighter on the northern flank of the Alps and in Grisons.
Fresh snow
The values below apply to altitudes above approximately 3000 m on the northern flank of the Alps, otherwise above approximately 2600 m:

From Wednesday afternoon until Thursday morning:
  • From the eastern Bernese Oberland across the Glarus Alps to northern Grisons and into Samnaun: 10 to 20 cm, but locally up to 40 cm
  • Other parts of the northern flank of the Alps and the other parts of Valais and Grisons: 5 to 15 cm
  • Elsewhere: dry
In the period from the start of precipitation on Monday until Thursday morning, the following amounts of snow fell:
  • Extreme west of Lower Valais and the northern flank of the Alps: mostly 50 to 100 cm
  • Rest of Valais, rest of the northern flank of the Alps, Prättigau and Samnaun: 30 to 50 cm
  • Less elsewhere, none in central and southern Ticino
Temperature
At midday at 2000 m: between +5 °C in the north and +7 °C in the south
Wind
Northwesterly
  • During the night on the northern Alpine ridge and the main Alpine ridge, strong to storm force, otherwise moderate at elevated altitudes
  • Easing gradually during the day
Weather forecast through Friday, 31.12.2021
After a clear night, it will be sunny and very mild for the time of year.
Fresh snow
-
Temperature
At midday at 2000 m: about +9 °C
Wind
From the west to northwest
  • Moderate to strong in the north
  • Light to moderate in the south
Outlook through Sunday, 02.01.2022
On New Year’s Day it will remain sunny and very mild in the mountains. On 2 January, cloud will build up from the northwest in the afternoon. The northwesterly wind will ease on New Year’s Day. On 2 January, the westerly wind will strengthen significantly. The avalanche danger will decrease.