With the mild weather, partly overcast nights and rain in places, moistening of the snowpackSnow deposited on the ground in a multiplicity of layers.EAWS glossary continued over the course of the last week. On south-facing slopes the snowpack is water-saturated up to around 3000 m, and on east- and west-facing slopes up to 2500 to 2700 m, while on north-facing slopes it is water-saturated below 2000 m, with moistening progressing between 2000 and 2400 m.

In the south, fresh and drifted snow at high altitudes is prone to triggering, especially on shady slopes. Avalanches can also in some cases still be triggered by human activity in faceted weak layersSnowpack layer in which the crystals are poorly bonded and the layer has the potential to fail. Typical crystals in dry weak layers causing avalanches are : precipitation particles; surface hoar; faceted crystals; hollow crystals; graupel. Generally >1mm in size, loose grains with few bonds Wet weak layers can be formed by all snow crystal/grain types.EAWS glossary in the old snowpackSnow layers deposited from earlier precipitation, prior to fresh fallen snow. Old snow layers consist of metamorphosed snow crystals.EAWS glossary. Such danger zonesLocations delineated by aspect or altitude where avalanches can trigger and people or objects are at risk.EAWS glossary are generally located at altitudes where the snowpackSnow deposited on the ground in a multiplicity of layers.EAWS glossary is becoming moist for the first time. In central Valais and in Grisons in particular, such avalanches can in some cases entrain the entire snowpack, especially on slopes with light snow cover.

Overnight to Monday, precipitation set in in the south, which became somewhat heavier as the day progressed. However, the precipitation was markedly lighter than expected. The snowfall level was around 2000 m.

Fresh snow

From Sunday evening to Monday afternoon above approximately 2400 m:

• main Alpine ridge in Upper Valais on the border with Italy from Monte Rosa to the Nufenen Pass, northwest Ticino: 30 to 50 cm, with up to 60 cm in Val Bedretto
• rest of main Alpine ridge from the Great St. Bernard Pass to the Bernina Pass, rest of Ticino, northern Alpine ridge from the Lötschental to the Reuss: 10 to 20 cm
• elsewhere a few centimetres or dry

Temperature

At midday at 2000 m, around +2 °C in the west and south and +4 °C in the east

Wind

Mostly moderate south to southeasterly at high altitudes, strong at times

There will be some widespread precipitation during the night. As the day progresses conditions will become increasingly sunny in Valais and in the south, while the north will be mostly cloudy. In the east in particular, light precipitation will continue until the afternoon. The snowfall level will be around 1600 to 2000 m, falling to 1200 m in the Jura.

Fresh snow

From Monday afternoon to Tuesday afternoon above approximately 2200 m:

• Monte Rosa region, Saas Valley, Simplon region, Val Müstair 10 to 15 cm
• elsewhere a widespread 5 cm, with up to 10 cm in the east

Temperature

At midday at 2000 m, between 0 °C in the north and +4 °C in the south

Wind

Light to moderate northeasterly

On Wednesday conditions will be very sunny in the mountains. In the south, there will be a possibility of isolated showers over the course of the day. On Thursday conditions will be very sunny in Valais and the south. In the north, the sometimes heavy broken cloud will mean only sunny intervals and the possibility of isolated showers. The zero-degree level will be around 2600 to 2800 m. Winds will mostly be light.

The danger of dry avalanches will decrease. The danger of wet avalanches will increase over the course of each day. Off-piste skiing and hut ascents should be completed in good time.