östliche Berner Voralpen

Snowpack

Sometimes large volumes of new fallen snow are being deposited on layers of fresh and drifted snow from the past few days. The underlying surface of the old snowpack was often faceted and weak, especially on shady slopes.

In the south, on the eastern part of the main Alpine ridge and in the Engadine, often even the entire old snowpack is faceted and loose, especially on shady slopes protected from the wind. Many avalanches were already being naturally triggered there even with Sunday’s snowfall. Given current snowfall, high avalanche activity is to be expected once again. 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 to Tuesday

Widespread precipitation, persistent and heavy in the southeast. The snowfall level will drop from 1800 m to around 1000 m in the north. In the south, it will briefly rise to 1900 m before dropping to 1200 m right at the end of the day. Over the course of the day, conditions will become dry for a short time in the west with brighter spells.

Fresh snow

From Monday afternoon to Tuesday afternoon, the following amounts of snow will fall above approximately 2000 m:

• Main Alpine ridge from the Lukmanier Pass to the Bernina Pass and south of there, with warning region Bivio and Upper Engadine: 50 to 80 cm
• extreme west of Lower Valais, Vaud and Fribourg Alps, rest of Ticino, rest of Grisons: 30 to 50 cm
• elsewhere: 20 to 30 cm.

Temperature

At midday at 2000 m, around -4 °C

Wind

• In the north and in Valais moderate and locally strong from the southwest to west
• In Ticino and Grisons, still sometimes storm force from the south during the night and moderate from the northwest during the day

Weather review for Monday

Conditions were very cloudy with foehn-like brighter spells in the north. Precipitation set in from the south-west. The snowfall level rose to 2000 m in the west and 1800 m in the east while it was around 1300 m in Valais and the south.

Fresh snow

Up until Monday afternoon, the following amounts of snow fell above approximately 2000 m:

• western and northern Lower Valais: 15 to 25 cm
• Ticino, southern Grisons: 10 to 15 cm
• elsewhere less; dry on the central and eastern parts of the northern flank of the Alps and in northern Grisons

Temperature

At midday at 2000 m between +2 °C in the north and -2 °C in the south

Wind

• Widespread strong to storm force southerly winds in Valais and the south
• foehn wind in the valleys of the north

Outlook

Overnight to Wednesday, with strong to storm force westerly winds in the west and north, there will be little snowfall above 1000 m, with at the most snow, 10 to 20 cm, falling in the extreme west of Lower Valais and the Vaud Alps. Conditions will then be mostly sunny on Wednesday. Thursday will be cloudy with brighter spells, and probable precipitation in the south, although amounts are still very uncertain.

The danger of dry avalanches will decrease, but only slowly in the south and in Grisons due to the weak snowpack structure. In these places, conditions outside secured pistes will remain critical. In addition, moist avalanches are to be expected on Wednesday due to the sunny conditions. Some of these may be large in those regions exposed to heavier precipitation in the south.