Wind slab
- All elevations
Considerable avalanche danger will be encountered in some regions.
Snowpack On north facing slopes above approximately 2500 m, fresh snow and snow drift accumulations are lying on loosely bonded layers; in Grisons, surface hoar has been covered with snow in some cases. Here in particular the near-surface layers are prone to triggering in some instances. On north facing slopes between 2000 and 2500 m, for the first time this winter the snowpack is becoming wet and consequently being weakened. At higher altitudes the upper layers have become moist. In Grisons in particular, in the last few days large avalanches have been released frequently in the deep, weak old snow on north facing slopes above approximately 2500 m. This danger still persists. In southern Valais and on the southern flank of the Alps, avalanches of this type can likewise not be ruled out. Observed weather review Monday, 24.04.2023 During the night a little precipitation fell over a wide area. The snowfall level was approximately 1700 m. During the day it remained mostly cloudy in the north. In the northeast in particular, a little precipitation continued to fall. The inneralpine regions were partly sunny, and the south was mostly sunny. Fresh snow From Sunday afternoon until Monday afternoon above approximately 2400 m:
Temperature At midday at 2000 m: about -1°C in the north and +2 °C in the south Wind On the northern flank of the Alps and at elevated altitudes sometimes strong, otherwise moderate; veering from southwesterly to northwesterly Weather forecast through Tuesday, 25.04.2023 The north will be very cloudy, and above approximately 1200 m snow will fall over a wide area. During the day there will be bright spells in the inneralpine regions. In the south the night will be partly clear, and during the day it will be fairly sunny. Fresh snow From Monday afternoon until Tuesday afternoon the following amounts of snow will fall above approximately 2400 m:
Temperature At midday at 2000 m: about -3°C in the north and -1 °C in the south Wind
Outlook through Thursday, 27.04.2023 Wednesday The night will be clear in the south. The skies will clear early in the night in the west, but not until Wednesday morning in the east. Wednesday will be sunny at times in the north and mostly sunny in the south and east. On Tuesday evening on the main Alpine ridge and to the south, strong, sometimes storm force from the northwest, before easing significantly and backing westerly. On the main Alpine ridge and to the south, snow drift accumulations may form at elevated altitudes. Otherwise, the danger of dry avalanches will decrease. As the day progresses, wet snow avalanches originating in the fresh snow are to be expected. Thursday Wednesday night will be partly clear; in the east it will remain overcast until the morning. During the day it will be fairly sunny. It will become warmer again; the zero degree level will rise to approximately 2500 m. The danger of dry avalanches will continue to decrease. The danger of wet snow avalanches will vary during the day.
As a consequence of new snow and a sometimes strong westerly wind, avalanche prone wind slabs will form. Single winter sport participants can release avalanches. The wind slabs are to be avoided in steep terrain. The prevalence of the avalanche prone locations will increase with altitude. Backcountry touring calls for experience in the assessment of avalanche danger and careful route selection.
The surface of the snowpack will cool hardly at all during the overcast night. In all aspects individual wet and gliding avalanches are possible below approximately 2200 m. These can reach large size in isolated cases.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)