Persistent weak layers
- Alle Höhenlagen
In the northeast a considerable avalanche danger will prevail.
Single winter sport participants can release avalanches in some places. These can be released in the weakly bonded old snow and reach medium size. These avalanche prone locations are to be found in particular on very steep north facing slopes. This applies in particular in little used backcountry terrain. Such avalanche prone locations are rare but are barely recognisable, even to the trained eye. The fresh and somewhat older wind slabs are in some cases prone to triggering. Careful route selection is recommended.
Snowpack In the central and eastern sectors of the northern flank of the Alps more than anywhere else, fresh snowdrift accumulations were generated at elevated altitudes on Friday night as a consequence of the fresh fallen snow accompanied by westerly winds. The snowfall on Saturday night was deposited with little wind impact, so that it can subsequently be transported to an intensive degree by rising bise winds on Sunday afternoon. Further to the west, the snow which has been deposited is unlikely to be transported. The snowdrift accumulations will be deposited on top of a rough-hewn and, therefore, favourable snowpack surface over widespread areas. Only on wind-protected high-altitude shady slopes will the snowdrift accumulations be deposited atop an expansively metamorphosed (faceted) and loose, therefore, less favourable snowpack surface. In the southern Valais and in the Grisons on northern slopes, the entire snow cover is expansively metamorphosed (faceted) and loose to a large degree. Snow depths throughout the Swiss Alps are far below average. At high altitudes in the flat fields where the measurement station devices make their recordings, they amount to only half of the customary values. Observed weather review Sunday, 26.02.2023 In the western regions at heightened altitudes it was partly sunny, in the other regions of Switzerland skies were predominantly overcast. During the night there was snowfall in the northeastern regions more than anywhere else, subsequently during the afternoon in the southern Valais. The snowfall level was in the low lying areas. Fresh snow Between Saturday afternoon and Sunday afternoon, the following amounts of fresh snow were registered:
Thus, on the northern flank of the Alps from the Titlis over the Glarus Alps as far as the Alpstein, overall 30 to 40 cm of fresh fallen snow has been registered above approximately 2000 m since Friday midday, more in some places in the Alpstein. Temperature At midday at 2000 m, -13 °C in the northern regions and -8 °C in the southern regions. Wind
Weather forecast through Monday, 27.02.2023 Particularly during the nocturnal hours, a small amount of snowfall is anticipated from region to region down to the low lying areas. During the daytime hours in the western sector of the northern flank of the Alps and in the Valais, it will be rather sunny. In the remaining regions of Switzerland there will be sunny intervals expected in the southern regions. Fresh snow Between Saturday afternoon and Sunday afternoon in the Valais part of the Main Alpine Ridge, 5 cm of fresh fallen snow is anticipated from region to region; in the other regions, less. Temperature At midday at 2000 m, -6 °C in the northern regions and -9 °C in the southern regions. Wind
Outlook through Wednesday, 01.03.2023 On Tuesday in the southern regions skies will be overcast, accompanied by a small amount of snowfall; in the other regions it will be partly sunny. The zero-degree level will ascend to approximately 2000 m. On Wednesday it will be predominantly sunny in the mountains. Winds will be blowing at light to moderate strength on both days. Avalanche danger levels are expected to incrementally decrease.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)