Zervreila

In the north, the sometimes storm-force northerly winds have been transporting the large volumes of fresh snow and, towards the south in particular, also the old snowpack. This has resulted in all regions in snowdrift accumulations that are prone to triggering; in the north these accumulations are large. Fresh and drifted snow has been deposited on variable snowpack surfaces: on north-facing slopes, especially in sheltered locations, onto very loose snow, whereas up to high altitudes on south-facing slopes often onto a crust. In many cases, the surface of the old snowpack has also been profiled by the wind and is irregular.

In the inneralpine regions of Valais and Grisons in particular, distinct weak layers remain in near-ground layers of the snowpack. In addition, near-surface layers in locations sheltered from the wind contain snow-covered surface hoar, in which avalanches have repeatedly been triggered over the last week. Given the fresh snowfall, avalanches are again likely to be triggered with increasing frequency in the old snowpack in these regions.

There was heavy precipitation in the north. The snowfall level was around 500 m. There were sunny intervals in the far south.

Fresh snow

From Wednesday afternoon to Thursday afternoon, the following amounts fell above 1000 m:

• northern Alpine ridge, central part of the northern flank of the Alps: 40 to 70 cm
• rest of the northern flank of the Alps, southern Lower Valais, rest of northern Grisons: 20 to 40 cm
• Jura, southern Goms, rest of central Grisons, Engadine north of the Inn: 10 to 20 cm
• less elsewhere, dry in the far south

Temperature

At midday at 2000 m, around -9 °C in the north and -4 °C in the south

Wind

Strong, and in the Jura and at high altitudes sometimes storm-force, north to northwesterly, easing off somewhat in the afternoon in the north

In the north, there will continue to be some widespread snowfall down to low altitudes until morning. Brighter periods will move in from the west over the course of the day. Conditions will be mosty sunny in southern Valais, Ticino and southern Grisons.

Fresh snow

From Sunday afternoon until precipitation stops around midday on Friday, the following amounts are expected above 1000 m:

• northern Alpine ridge: 10 to 20 cm
• rest of the northern flank of the Alps, southern Lower Valais, northern and central Grisons: 5 to 10 cm
• elsewhere less or dry

Temperature

Cold, at midday at 2000 m around -10 °C in the north and -4 °C in the south

Wind

• Strong to storm force northerly during the night
• Over the course of the day, the wind will veer northeasterly and will mainly be moderate to strong; there will be a strong Bise wind in the Jura and the western Prealps

Saturday

After a clear night, conditions will initially be sunny on Saturday. Clouds will gather from the northwest in the afternoon. Conditions will remain sunny all day in the south and in Grisons. There will be light to moderate winds from northerly directions. The zero-degree level will rise to around 2000 m in the south, while in the north temperatures will remain cool with a zero-degree level of around 1200 m.

The danger of dry avalanches will fall in all regions. With solar radiation, moist snow slides are to be expected in the fresh snow during the day.

Sunday

There will be heavy cloud cover in the north on Sunday and there will be a widespread 5 to 15 cm of fresh snow down to low altitudes. Conditions will be quite sunny in the south. There will be an often moderate northeasterly wind which will become strong at times at high altitudes. There will be an increasingly strong Bise wind in the Jura and the western Prealps.

There will be no significant change in avalanche danger.