Snowpack

The masses of fresh snow from Wednesday have been transported intensively in the western regions more than anywhere else.
Beneath the layers of fresh fallen snow and freshly generated snowdrifts from last week, the old snow is thoroughly wet below approximately 3000 m on east-facing, south-facing and west-facing slopes; beneath 2200 to 2500 m on north facing slopes. As a result of the predominantly gray skies, the process of snowpack moistening will not progress further on Thursday.

Observed weather on Wednesday, 05.05.2021

In the furthermost eastern regions, nighttime skies were clear; elsewhere skies were overcast and there was precipitation over widespread areas. The snowfall level in northern regions descended from 1800 down to 1300 m.

Fresh snow

By Wednesday midday the following amounts of fresh snow were registered above approximately 2000 m:

northern flank of the Alps, northern Valais, western Lower Valais, Gotthard region: 10 to 20 cm; in the furthermost western regions as much as 30 cm;
in the other regions of Switzerland, less than 10 cm; in the furthermost southern regions and in the Upper Engadine it remained dry.

Temperature

At midday at 2000 m, between -3 °C in the northern regions and +1 °C in the southern regions.

Wind

Winds were blowing at moderate to strong velocity from southwesterly directions.

Weather forecast through Thursday, 06.05.2021

On Wednesday evening in the northeastern regions there will still be a small amount of sunshine, subsequently it will be dry in all regions of Switzerland, with bright intervals in the southern regions. On Thursday morning in the southern regions it will be partly sunny, in the other regions of Switzerland skies will be overcast. At midday precipitation will set in from the west. The snowfall level will ascend to 2200 m by evening in the western regions, up to 1800 m in the eastern regions.

Fresh snow

Between Wednesday afternoon and Thursday afternoon, the following amounts of fresh snow are anticipated:

furthermost western part of Lower Valais, Vaud Alps: 10 to 15 cm;
northern part of Lower Valais: 5 to 10 cm;
in the other regions of Switzerland, less; in Grisons and the southern regions, it will remain predominantly dry.

Temperature

At midday at 2000 m between +2 °C in the northern regions and 0 °C in the southern regions.

Wind

During the nighttime hours, a moderate-to-strong velocity westerly-to-northwesterly wind will be blowing;
during the daytime hours, a strong velocity westerly-to-southwesterly wind will be blowing, becoming increasingly stormy in northern regions in the afternoon.

Outlook through Saturday, 08.05.2021

Friday

Skies will be heavily overcast, accompanied by precipitation. In the western and the northern regions, 20 to 40 cm of fresh snow is expected; in the furthermost western regions of Lower Valais, approximately 50 cm. The snowfall level will gradually descend to approximately 1500 m. Until early morning hours, winds will be blowing predominantly at strong velocity from westerly to northwesterly directions. In the southern regions it will become quite sunny during the course of the day, as a consequence of northerly winds.
Avalanche danger levels are expected to increase significantly in the northern regions and the western regions. The avalanche situation will be most critical in the furthermost western part of Lower Valais. In the southern regions and in Grisons, avalanche danger levels are not expected to change significantly.

Saturday

On Saturday it will be predominantly sunny and become noticeably milder during the course of the day. The zero-degree level in the western and the southern regions will ascend to significantly over 3000 m.
The danger of dry-snow avalanches will decrease. As a result of solar radiation and the significant daytime warming, moist-snow slides and avalanches can be expected even at high altitudes. In the major areas of precipitation these releases can grow to large size.