For those venturing off piste a sometimes critical avalanche situation will prevail
Edition: 4.12.2021, 17:00 / Next update: 5.12.2021, 18:00
Snowpack
Snow has fallen everywhere during the last seven days, in the northern regions a great deal. The fresh snow and fresh drifts from this period were deposited on top of a shallow but weak old snowpack. Thus, the snowpack layering is unfavourable, particularly on west-facing, north-facing and east-facing slopes above 2000 m.
On Saturday in the western and the northern regions, additional snowdrift accumulations were formed as a result of snowfall and storm-strength winds; drifts will continue to be generated well into the night on Saturday.
Below approximately 1500 to 2000 m, rainfall moistened the snow on the ground. Intense activity of moist-snow avalanches was reported in some places.
Observed weather on Saturday, 04.12.2021
Skies were heavily overcast. During the night in the western and the northern regions, intensive precipitation set in. To begin with it snowed down to low lying areas. Subsequently the snowfall level ascended up to 1500 to 2000 m in many places. In the southern regions it was dry and partly sunny.
Fresh snow
By Saturday afternoon the following amounts of fresh snow were registered above approximately 2000 m:
  • northern Alpine Ridge west of the Blüemlisalp: 40 to 60 cm;
  • remaining regions of the northern flank of the Alps, of northern Valais and of the furthermost western part of Lower Valais: 20 to 40 cm;
  • remaining parts of Valais not including the valleys of Visp, Grisons north of the Anterior Rhine, northern Prättigau: 10 to 20 cm; in the other regions of Switzerland, less, or else it remained dry.
Approximately 30 cm of wet snowfall was registered on the highest summits of the Jura region.
Thus, within one week, the following overall amounts of fresh snow were registered above 1800 m:
  • northern flank of the Alps, furthermost western part of Lower Valais: 100 to 150 cm, more than 200 cm in parts of the Glarus Alps;
  • northern Valais, Grisons north of the Anterior Rhine, Prättigau: 60 to 100 cm;
  • in the other regions of Switzerland, 20 to 60 cm over widespread areas.
Temperature
At midday at 2000 m, +1°C in the northern regions and -6 °C in the southern regions.
Wind
Winds were blowing from westerly directions:
  • in the northern regions and the Valais frequently at strong velocity;
  • in Grisons and in the Ticino predominantly at moderate strength.
Weather forecast through Sunday, 05.12.2021
In the northern and western regions, ongoingly intensive precipitation is expected to continue during the early part of the night, with the snowfall level swiftly descending down to low lying areas. Subsequently, skies will continue to remain heavily overcast, accompanied by snowfall down to low lying areas. In the southern regions it will be rather sunny on Sunday.
Fresh snow
Between Saturday afternoon and Sunday afternoon, the following amounts of fresh snow are anticipated above approximately 2000 m:
  • northern Alpine Ridge west of the Reuss, Vaud and Fribourg Alps, as well as the furthermost western part of Lower Valais: 20 to 30 cm, as much as 40 cm along the French border;
  • remaining parts of the northern flank of the Alps, remaining parts of Lower Valais, northern Grisons: 10 to 20 cm;
  • in the other regions of Switzerland, less; in the southern regions it is expected to remain dry;
  • in the Jura region above 1200 m: 10 to 20 cm.
Temperature
At midday at 2000 m, -8 °C.
Wind
  • Strong westerly winds will be blowing at high altitudes and on the northern flank of the Alps during the early part of the night;
  • subsequently, light to moderate-strength westerly winds; in the southern regions winds will be northwesterly.
Outlook through Tuesday, 07.12.2021
Monday
In the northern regions skies will be overcast and a few centimetres of snow is expected to fall down to low lying areas. In the inneralpine regions, bright intervals are anticipated. In the furthermost southern regions it will be predominantly sunny.
The avalanche danger levels are expected to decrease. However, except in the southern regions avalanche conditions in outlying terrain beyond secured public ski slopes are expected to remain treacherous for winter sports enthusiasts.
Tuesday
On Monday night, a small amount of snowfall is expected to extend down to the valley floor over widespread areas. On Tuesday it will become quite sunny from the west, though in the eastern regions skies are expected to remain overcast for longer. In the southern regions it will be sunny.
Avalanche danger levels will decrease in the northern regions. In the inneralpine regions and the south, avalanche danger is not expected to change significantly.