Monthey-Val d'Illiez

Considerable avalanche danger will be encountered over a wide area.

Snowpack

The fresh fallen snow of the last two days has been intensively transported by strong to storm-strength winds from northerly directions. Fresh snow and freshly generated snowdrift accumulations were frequently deposited on top of a relatively unfavourable old snowpack surface. In more deeply embedded layers inside the snow cover, crusts have been generated as a consequence of repeated bouts of rainfall and subsequently descending temperatures. These layers are predominantly compact and stable. However, above approximately 2600 m there is an expansively metamorphosed (faceted) layer wedged between generally thin crusts which constitutes a potentially weak layer.

Weather forecast through Monday, 27.11.2023

During the daytime hours, skies will in general be heavily overcast. During the afternoon in the western regions, a small amount of precipitation is anticipated from region to region. The snowfall level will lie between 800 and 1000 m.

Fresh snow

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Temperature

At midday at 2000 m, between -2 °C in the northern regions and -6 °C in the southern regions.

Wind

Winds will be blowing from westerly to southwesterly directions,

• intensifying during the course of the day and blowing at moderate to strong velocity on the northern flank of the Alps and in general at heightened altitudes;
• blowing at light to moderate strength on the southern flank of the Alps.

Observed weather review Sunday, 26.11.2023

It was already sunny in early morning in the western and the southern regions, while in northeastern regions the last bit of snowfall was registered. During the daytime hours it then remained generally dry and turned increasingly sunny from the west. In the eastern sector of the northern flank of the Alps, however, skies remained overcast.

Fresh snow

The snowfall level lay below 500 m. Between Saturday midday and Sunday midday the following amounts of fresh snow were registered:

• Urner and Glarus Alps, upper Prättigau: 30 to 50 cm;
• remaining parts of northern Alpine Ridge, remaining parts of northern Grisons: generally 15 to 30 cm;
• in the other regions of Switzerland, less; in the furthermost southern regions it remained dry.

Thus, the following overall amounts of snowfall have been registered since the beginning of this period of precipitation on Thursday night:

• Urner and Glarus Alps, upper Prättigau, Silvretta: 50 to 80 cm:
• remaining parts of northern Alpine Ridge, remaining parts of northern Grisons: generally 30 to 50 cm;
• further towards the north and towards the south, less; in the Jura region, along the Prealps, from southern Valais over northern Ticino into the southern part of Upper Engadine: 5 to 15 cm;
• in the other regions of Switzerland, less; in the furthermost southern regions it remained dry.

Temperature

At midday at 2000 m, between -8 °C in the northern regions and -2 °C in the furthermost southern regions.

Wind

Winds were blowing from northerly to northwesterly directions,

• predominantly at strong velocity at high altitudes until Sunday morning;
• slackening off during the course of the day, blowing at light strength, at high altitudes mostly at moderate strength.

Outlook through Wednesday, 29.11.2023Tuesday

In the northern regions, snowfall is anticipated down to low lying areas, accompanied by strong to storm-velocity northwesterly winds. Most of the snowfall is expected on the northern Alpine Ridge: 30 to 60 cm. Avalanche danger levels are expected to increase, significantly so in the major areas of precipitation. On the southern flank of the Alps only a small amount of snowfall is anticipated. In the furthermost southern regions it will remain dry and predominantly sunny. Avalanche danger is not expected to change significantly.

Wednesday

On Tuesday night the precipitation will come to an end. During the daytime hours on Wednesday it will temporarily be predominantly sunny in all regions of Switzerland. Winds are expected to slacken off somewhat, nevertheless at high altitudes still be blowing at moderate to strong velocity from westerly directions. Avalanche danger levels will decrease somewhat, however the situation in the major areas of precipitation will still remain critical for snow sports in outlying terrain away from secured ski pistes.