Moderate avalanche danger will be encountered over a wide area
Edition: 28.4.2021, 17:00 / Next update: 29.4.2021, 18:00
Snowpack
The fresh snow is being deposited on top of a moist old-snowpack surface over widespread areas. On steep north-facing slopes above approximately 2800 m there is still loosely-packed snow in some places. The moderate to strong-velocity southwesterly winds are transporting the fresh fallen snow, snowdrift accumulations which are prone to triggering are being generated in some places.
The snowpack is thoroughly wet on south-facing slopes below approximately 3000 m, on east-facing and west-facing slopes below approximately 2800 m. On north-facing slopes the process of snowpack moistening is progressing at altitudes between 2200 and 2400 m.
During the last few days, only very few wet-snow and gliding avalanches have been reported. Gliding avalanches can grow to large size in the regions where snowfall has been heaviest.
Observed weather on Wednesday, 28.04.2021
Skies were heavily overcast for the most part, accompanied by extended bright intervals in Grisons more than anywhere else. In the furthermost western regions, shower activity set in during Wednesday night.
Fresh snow
Until afternoon above approximataely 2500 m,
  • in the northern and furthermost western regions of Lower Valais: 5 to 10 cm;
  • in the other regions of Switzerland, less; or else 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 predominantly light, blowing intermittently at moderate strength from southerly directions.
Weather forecast through Thursday, 29.04.2021
Skies will be heavily overcast for the most part, and precipitation is expected in the western and southern regions more than anywhere else. In inneralpine regions, short bright intervals are possible.
Fresh snow
The snowfall level will lie between 1800 and 2200 m. Above 2500 m:
  • northern and furthermost western part of Lower Valais, Main Alpine Ridge from Great St. Bernard into the Bernina region: 15 to 30 cm, up to 40 cm from place to place;
  • remaining parts of Valais, remaining parts of the northern Alpine Ridge: 5 to 15 cm;
  • in the other regions of Switzerland, less; further towards Lower Engadine 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
Winds at heightened altitudes will be blowing at moderate to strong velocity from southwesterly directions; foehn wind will prevail in the Alpine valleys of the north.
Outlook through Saturday, 01.05.2021
Friday
On Thursday night, precipitation will move further towards the east. During the daytime hours on Friday, it will initially be variably cloudy in the northern regions, accompanied by bright intervals in the Valais more than anywhere else, as well as further to the east. Subsequently, showers will arise increasingly from the west. In the southern regions skies will be overcast, accompanied by light precipitation, which is expected to intensify as evening approaches. The snowfall level will lie at approximately 2200 m. The avalanche danger levels are not expected to change significantly.
Saturday
Skies are expected to be heavily overcast by and large. During the morning hours in the inneralpine regions, bright intervals are possible. Precipitation is anticipated over widespread areas, with the focal point on the Main Alpine Ridge and southwards therefrom. The snowfall level will lie at 2200 m. There, 20 to 40 cm of fresh snow is expected. The danger of dry-snow avalanches will increase in the major areas of precipitation more than anywhere else. The danger of wet-snow and gliding avalanches is not expected to change significantly.