Bulletin d’avalanche

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Danger d’avalanche

All elevations
2= · Modéré
Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Increase in avalanche danger in the west and in the north.

Problèmes avalancheux

  • Wind slab

    • Above 2,200 m
  • Gliding snow

    • Toutes altitudes

Snowpack Structure

Snowpack

In the Lower Valais, in the northern part of the Upper Valais and in the southern part of the Engadine, there is already a greater than average amount of snow on the ground. The snow cover in these regions is favourably layered for the most part and winter sports in the snow are easily possible. In the remaining regions of Switzerland there is also a snowpack over widespread areas above the treeline, which however is exceedingly thin, makinig it too shallow for snow sports. In these regions more than anywhere else the snowpack manifests severe effects from wind impact, the snowpack on the northern flank of the Alps, furthermore, shows the effects of warmth. On north-facing slopes above approximately 2200 to 2400 m in particular, the shallow snowpack is metamorphosed (faceted) in some places, thus making it a relatively unfavourable base for the snowfall which is approaching.

Weather Forecast

Weather forecast through Saturday, 11.11.2023

In the northern regions skies are expected to be heavily overcast accompanied by snowfall. The snowfall level will lie at 1000 m. In the southern regions it is expected to be sunny.

Fresh snow

Between Friday afternoon and Saturday afternoon, the following amounts of fresh snow are anticipated above approximately 1200 m:

  • furthermost western part of the Lower Valais as well as north of an imaginary Rhine-Rhone line: 20 to 40 cm;
  • remaining parts of the Valais, southern part of Gotthard region, Prättigau: 10 to 20 cm;
  • in the remaining regions of Switzerland, only a few centimetres; it is expected to stay generally dry on the southern flank of the Alps.

Temperature

At midday at 2000 m, -5 °C in the northern regions, -3 °C in the southern regions.

Wind

  • Winds in the Valais and on the northern flank of the Alps: blowing at strong to storm velocity during the nocturnal hours from westerly directions, slackening off somewhat during the daytime hours;
  • Grisons: moderate to strong velocity northwesterly winds at high altitudes;
  • Ticino: moderate strength northerly winds.

Weather Review

Observed weather review Friday, 10.11.2023

Skies were predominantly overcast and there was intermittent snowfall registered. The snowfall level lay at 1000 to 1300 m.

Fresh snow

Between Thursday afternoon and Friday afternoon, the following amounts of fresh fallen snow were registered:

  • northern Alpine Ridge from the Chablais into the Lötschental: 20 to 35 cm;
  • remaining parts of the western and central sectors of the northern flank of the Alps, remaining parts of the Valais, northern Ticino: 10 to 20 cm;
  • in the other regions of Switzerland, less; or else it remained dry.

Temperature

At midday at 2000 m, -2 °C.

Wind

Winds were blowing from southwesterly directions,

  • in the western and the northern regions at moderate strength, in isolated cases at strong velocity;
  • in the Ticino and in Grisons blowing predominantly at weak to moderate strength.

Tendency

Outlook through Monday, 13.11.2023

In the Valais, on the northern flank of the Alps and in the northern part of Grisons, skies will predominantly be heavily overcast and snowfall is anticipated. The snowfall level is expected to ascend during the course of the day on Sunday to nearly 1800 m, approaching from the west; on Monday, to 2400 m. Above 2500 m, 40 to 80 cm of fresh fallen snow is anticipated. Avalanche danger levels will increase particularly at heightened altitudes, from region to region danger level 4 (high) could be reached. Below 2500 m, wet-snow avalanches can be expected. In central Grisons and in the Engadine, skies will also be predominantly overcast, and approximately 10 to 30 cm of fresh snow can be expected. The avalanche danger levels will increase only slightly. In the Ticino and the southern valleys of Grisons, it is expected to be partly sunny – particularly on Sunday – and hardly any snowfall is anticipated. Avalanche danger levels are not expected to change significantly.

Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)

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