By Tuesday evening, snowdrift accumulations that are sometimes prone to triggering will have developed at high altitudes on the main Alpine ridge. These will be medium-sized on the main Alpine ridge in Valais while further east they will still mostly be small.

Over the often cloudy night into Tuesday, the surface of the snowpack will barely freeze, even at high altitudes. Despite the slight decrease in temperature, wet avalanches remain possible, especially on north-facing slopes between 2200 and 2600 m, where the snowpack is becoming saturated for the first time.

The night into Monday was mostly cloudy and outgoing longwave radiation was low. Skies were mostly cloudy during the day. In Valais, a little snow fell above approximately 2300 m. In the east, there were sometimes extended bright spells.

Fresh snow

Five to 10 cm on the main Alpine ridge in Valais above approximately 2300 m and a few centimetres locally in the rest of Valais

Temperature

At midday at 2000 m, between +9 °C in the north and +6 °C in the south

Wind

Moderate to strong from the south

Conditions will be mostly cloudy on the main Alpine ridge and south of there. Snow will fall at times above approximately 2000 m. Otherwise, conditions will be variably cloudy with extended bright spells in central Valais and those regions exposed to the foehn wind in central and eastern Switzerland.

Fresh snow

From Monday afternoon until Tuesday afternoon above approximately 2500 m:

• main Alpine ridge in Valais: 15 to 25 cm
• Aletsch region, main Alpine ridge from the Nufenen Pass to the Bernina region and south of there: 5 to 10 cm

Temperature

At midday at 2000 m, between +7 °C in the north and +2 °C in the south

Wind

Southerly

• strong at times overnight
• during the day, moderate to strong in the east, moderate in the west

On Wednesday and into the night to Thursday, there will be frequent precipitation. The snowfall level will initially be at 2000 m, dropping to 1800 m as the snowfall comes to an end. On Thursday, it will initially still be cloudy in the east and south, and very sunny in the west. Over the course of the day, alongside brighter spells, there is a possibility of cumulus clouds and isolated showers in all regions. On Wednesday, there will be sometimes strong southerly winds at high altitudes; elsewhere winds will be mostly light to moderate from the southwest. By Thursday night, 30 to 50 cm of snow is expected from eastern Ticino to the Bernina region and to the south of there above approximately 2500 m. In the Glarus Alps, in the Gotthard region and in central Grisons, up to 30 cm of fresh snow is expected with up to 20 cm falling in other regions.

There will be a widespread increase in the danger of dry avalanches in high altitudes, the danger rising significantly on Wednesday on the main Alpine ridge from eastern Ticino to the Bernina region. On Thursday, the avalanche situation will remain critical for snow sport participants, especially at high altitudes in those regions exposed to heavier precipitation. In all regions, there is still a possibility of isolated wet avalanches being triggered in deep layers of the snowpack, especially on north-facing slopes between 2200 and 2600 m.