Zervreila

Especially on wind-protected shady slopes, fresh and drifted snow is lying on an old snow surface that is faceted in many places, and sometimes also on surface hoar. The connection to the old surface of the snowpack is poor in many places. Deeper layers of the snowpack are relatively well consolidated in the extreme west of Lower Valais and on the northern flank of the Alps. South of a line from the Rhône to the Rhine, the entire snowpack is often faceted and loose. Where fresh and drifted snow is deposited on this weak snowpack, avalanches can start deeper in the snowpack.

There were clear spells, especially in Grisons, otherwise conditions were mainly heavily overcast. There was sometimes heavy snowfall during the night in the west and north. There were snow showers but also some breaks in the precipitation during the day.

Fresh snow

From Thursday afternoon to Friday afternoon, 20 to 40 cm fell in Valais and on the northern Alpine ridge, and up to 60 cm in the extreme west of Lower Valais. This means that the following amounts of snow have fallen above around 1500 m since precipitation began on Wednesday evening:

• northern Alpine ridge from Les Diablerets to the Aletsch region, extreme west of Lower Valais, Main Alpine Ridge of the Valais from Val Ferret to Monte Rosa: 40 to 60 cm, locally up to 80 cm
• rest of northern flank of the Alps apart from the Prealps, rest of Valais, Gotthard region, northern Grisons, Samnaun: 20 to 40 cm
• Jura, Prealps, central Grisons, Engadine apart from Samnaun: 10 to 20 cm
• elsewhere less or dry

Temperature

At midday at 2000 m, around -5°C

Wind

Westerly:

• moderate to strong in the west and north
• mainly light to moderate in the south and in Grisons

Conditions will be mainly heavily overcast with snowfall down to low altitudes in the north while in the south there will be variable cloud cover with bright spells over the course of the day.

Fresh snow

From Friday afternoon to Saturday afternoon above approximately 1200 m:

• western Jura, extreme west of Lower Valais, northern Alpine ridge: 20 to 40 cm
• eastern Jura, rest of Valais west of the Mattertal, other regions of the northern flank of the Alps, northern Prättigau: 15 to 30 cm
• Visp valleys, Simplon region, southern Goms, southern Gotthard region, rest of northern Grisons, northern Lower Engadine: 5 to 15 cm
• further south a few centimetres or dry

Temperature

At midday at 2000 m, around -10°C in the north and -7°C in the south

Wind

Strong westerly to northwesterly, especially in the west and north

Snowfall will pick up again in the north overnight to Sunday. Between Saturday afternoon and Sunday morning, another 20 to 40 cm of snow may fall on the northern flank of the Alps. On Sunday, there will be sunny spells in the north while conditions will be mainly sunny in the south. On Monday, conditions will mainly be overcast in the north, but with only little snowfall. There will be sunny spells in the far south on Monday.

Avalanche danger will increase overnight to Sunday on the northern flank of the Alps where naturally triggered avalanches are to be expected. Avalanche risk will slowly decrease in the north on Sunday and Monday. Especially in those regions to the south of a line from the Rhône to the Rhine, the weak old snowpack means that this decrease will be only very slow.