Bulletin d’avalanche

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Danger d’avalanche

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

Problèmes avalancheux

  • New snow

    • Above 2,000 m
  • Persistent weak layers

    • Above 2,000 m

Snowpack Structure

Snowpack

With winds from the west and south and mild temperatures, recent days have seen the formation of often hard snowdrift accumulations. Particularly adjacent to ridgelines and in the vicinity of passes, the surface of the snow has been shaped significantly by the wind and is therefore irregular. With new snow falling and the wind from the southwest, fresh snowdrift accumulations will develop on Sunday.

In the south and in the Engadine, the entire snowpack has become faceted and loose, especially on shady slopes protected from the wind. Over the next few days, a lot of fresh snow will be deposited on this very weak snowpack from eastern Ticino to Upper Engadine. North of a line from the Rhône to the Rhine and in the extreme west of Lower Valais, the middle part of the snowpack is often well consolidated, and there is little likelihood of avalanches deep in the old snowpack.

Weather Forecast

Weather forecast to Sunday

There will be widespread precipitation overnight to Sunday, especially in the south. The snowfall level will initially be around 1700 m in the north and 1400 m in the south, dropping to around 1200 m everywhere. During the day it will be quite sunny in the west, with bright intervals in the south and east in the afternoon.

Fresh snow

From Saturday afternoon to Sunday afternoon:

  • main Alpine ridge from the Lukmanier Pass to the Bernina area and south from there: 30 to 50 cm
  • extreme west of Lower Valais, Vaud Alps and the rest of Ticino: 15 to 30 cm
  • elsewhere a widespread 5 to 15 cm

Temperature

At midday at 2000 m, between 0 °C in the north and -2 °C in the south.

Wind

From the south-west:

  • during the night in the east and generally at high altitudes initially strong to storm-force, elsewhere moderate to strong, with a strong foehn wind from the south in the valleys of the north
  • mostly moderate during the day

Weather Review

Weather review for Saturday

In the north conditions were mostly sunny with foehn winds, while the south was very cloudy.

Fresh snow

-

Temperature

At midday at 2000 m, between +5 °C in the north and -1 °C in the south

Wind

From the south-west:

  • moderate to strong in the north, moderate to strong foehn wind from the south in the Alpine valleys
  • moderate at high altitudes in the south

Tendency

Outlook

On Monday it will be very cloudy with strong to storm-force southwesterly winds. Foehn-like bright intervals are possible in the east. Widespread precipitation from the west and south will set in in the morning, which will continue into Tuesday and be particularly heavy in the south. Monday to Tuesday afternoon will see a widespread 20 to 40 cm of fresh snowfall, with 50 to 80 cm on the main Alpine ridge from the Lukmanier Pass to the Bernina and south from there. The snowfall level will initially be between 1800 m in the west and 1400 m in the south. During the night to Tuesday, this will drop to around 1200 m.

There will be a widespread increase in avalanche danger. In the night to Tuesday, danger level 4 (high) is expected to be reached from eastern Ticino via Val Moesa, Rheinwald, Avers and Val Bregaglia to the Bernina region. Numerous moderate and large naturally triggered avalanches are expected in these regions. Very large avalanches may also occur, especially in the high Alpine regions, but they will not advance all that far because there is very little snow in the avalanche tracks. However, high-altitude transport routes will be at risk. The avalanche situation for winter sport participants will also become critical in the far west and in the other regions of Grisons and Ticino.

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

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