Bulletin d’avalanche

Pays d'Enhaut

SLF
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Danger d’avalanche

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

Points saillants

Considerable avalanche danger will be encountered over a wide area.

Problèmes avalancheux

  • New snow

    • Above 2,000 m

Snowpack Structure

Snowpack

Fresh snow and freshly generated snowdrift accumulations have frequently been deposited on top of expansively metamorphosed (faceted), relatively unfavourable layers of snow and are prone to triggering. As a consequence of persistent snowfall and strong-velocity northerly winds, the snowdrift accumulations will continue to grow in magnitude. The snowdrifts are thickest in the major areas of precipitation on the northern flank of the Alps and in northern Grisons. In the remaining regions of Switzerland the snowdrift accumulations are less large, but frequently just as prone to triggering. More deeply embedded layers inside the snow cover are predominantly compact and stable as a result of repeated bouts of rainfall up to high altitudes followed by descending temperatures.

Weather Forecast

Weather forecast through Sunday, 26.11.2023

On Saturday night, snowfall down to low lying areas is anticipated over widespread regions, most of which is expected to fall on the northern flank of the Alps and in northern Grisons. During the daytime hours on Sunday, it will become increasingly sunny in the western regions and in the Valais, in the southern regions it will be predominantly sunny. In the eastern regions skies will remain overcast and a small amount of snowfall is still expected.

Fresh snow

Between Saturday evening and Sunday afternoon, the following amounts of fresh snow are anticipated above approximately 1500 m:

  • northern Alpine Ridge from the Wildstrubel as far as Liechtenstein, northern Grisons, Lower Engadine north of the Inn: 20 to 30 cm;
  • northern Alpine Ridge west of the Wildstrubel, remaining regions of the central and eastern sectors of the northern flank of the Alps, Upper Engadine north of the Inn: 10 to 20 cm;
  • in the other regions of Switzerland: 5 to 10 cm over widespread areas; in the furthermost southern regions it will remain dry.

Temperature

At midday at 2000 m, -8 °C, temperatures rising somewhat during the afternoon from the west.

Wind

Winds will be northerly to northwesterly,

  • during the nocturnal hours blowing predominantly at strong velocity, in some places in the high alpine regions blowing at storm strength;
  • slackening off during the daytime hours, blowing at light to moderate strength at 2000 m.

Weather Review

Observed weather review Saturday, 25.11.2023

During the nocturnal hours on Friday there was snowfall down to low lying areas over widespread regions, intensive snowfall on the northern flank of the Alps. During the daytime hours on Saturday the snowfall temporarily slackened off and subsequently set in once again during the afternoon. In the furthermost southern regions it was quite sunny.

Fresh snow

Between Friday afternoon and Saturday afternoon, the following amounts of fresh snow were registered above approximately 1500 m:

  • from the eastern part of the Bernese Oberland over the Urner into the Glarus Alps: 30 to 50 cm;
  • remaining parts of the northern Alpine Ridge from the Dent des Morcles as far as Liechtenstein, northern Grisons, Lower Engadine north of the Inn: 20 to 40 cm;
  • remaining sectors of the northern flank of the Alps, Lower Valais, Goms, Gotthard region, central Grisons, Upper Engadine north of the Inn, remaining parts of Lower Engadine: 10 to 20 cm;
  • in the other regions of Switzerland, less; in the furthermost south it remained dry.

Temperature

At midday at 2000 m, -10 °C.

Wind

Winds were blowing predominantly at strong velocity, intermittently at storm strength at high altitudes, from westerly to northerly directions.

Tendency

Outlook through Tuesday, 28.11.2023Monday

As a consequence of the westerly to southwesterly winds, skies will be predominantly overcast, but it will remain dry to start with. During the course of the day a small amount of snowfall is anticipated, more than anywhere else in the northern and the western regions above approximately 800 m. Avalanche danger levels are expected to decrease somewhat. Naturally triggered avalanches are no longer to be expected. Nevertheless, avalanches continue to be easily triggerable by persons.

Tuesday

Except for in the furthermost southern regions, snowfall is expected down to low lying areas in widespread regions, most of which will fall on the northern Alpine Ridge and in the furthermost western parts of the Lower Valais. In those regions, 40 to 60 cm of fresh fallen snow can be expected. As a consequence of fresh snowfall and strong to storm-strength northwesterly winds, avalanche danger levels will again increase, significantly so on the northern Alpine Ridge and in the Lower Valais. Conditions for winter sports in outlying terrain away from secured ski pistes are critical, particularly so in the major areas of precipitation.

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

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