In the early morning a generally favourable avalanche situation will prevail. Wet avalanches as the day progresses
Edition: 21.4.2021, 17:00 / Next update: 22.4.2021, 18:00
Snowpack
Dry-snow avalanches can be triggered in the near-surface layers of the snowpack in isolated cases. These generally sweep away the fresh snow and freshly-generated snowdrifts of last week. As a result of the predominantly light winds, only small-sized ridgeline snowdrift accumulations are being generated in the areas of fresh snowfall.
During a night of predominantly overcast skies on Wednesday night, the surface of the snowpack is barely able to cool. Thus, the danger of wet-snow avalanches will increase to a greater extent during the course of the day than on previous days. Since Tuesday, gliding avalanches have again been reported.
Observed weather on Wednesday, 21.04.2021
On Wednesday night in the southern regions skies were overcast, in the other regions of Switzerland mostly clear. In the early morning hours on Wednesday it was partly sunny, subsequently cloud cover rapidly moved in from the west. In the northeastern regions it remained partly sunny until afternoon. In the southern regions, both nighttime skies and daytime skies were overcast. In the Valais sector of the Main Alpine Ridge and in the Ticino, a small amount of snowfall was registered above approximately 1500 m.
Fresh snow
  • Valais sector of Main Alpine Ridge, Ticino: a few centimetres from place to place;
  • in the other regions of Switzerland it remained predominantly dry until afternoon.
Temperature
At midday at 2000 m, 0 °C over widespread areas, in the southern regions at +2 °C.
Wind
Winds were light.
Weather forecast through Thursday, 22.04.2021
Nocturnal skies will be predominantly overcast, over widespread areas a small amount of precipitation is anticipated, falling as snow above approximately 1700 m. On Thursday morning in the northeastern regions, a few clouds will persist, elsewhere it will be generally sunny. During the course of the day, convective cloud build-up is anticipated, and isolated showers are possible.
Fresh snow
Between Wednesday midday and the end of this period of precipitation on Wednesday night, the following amount of fresh snow are expected over widespread areas:
  • southern Valais: 10 to 15 cm, also more from place to place as showers;
  • western sector of the northern flank of the Alps, northern Valais: approximately 5 to 10 cm, also more from place to place as showers;
  • in the other regions of Switzerland, less than 5 cm.
Temperature
At midday at 2000 m, between +3 °C in the southern regions and +1 °C in the northeastern regions.
Wind
Winds will shift to northeasterly, and continue blowing at mostly light strength.
Outlook through Saturday, 24.04.2021
Following nights of predominantly clear skies with adequate outgoing longwave radiation it will be sunny and gradually milder each day. Winds will remain light.
The danger of dry-snow avalanches will decrease. During the course of the day, increasingly frequent wet-snow and gliding avalanches can be expected. Backcountry tours should be brought to a close early in the day.