Wind slab
- All elevations
Considerable avalanche danger will be encountered over a wide area.
The fresh and older wind slabs represent the main danger. They are only small but in some cases prone to triggering. Even a small avalanche can sweep snow sport participants along and give rise to falls.
Avalanche bulletin survey: intermediate levels - helpful or confusing? Link to the survey in AvaBlog (on SLF-App WhiteRisk or at slf.ch)
Snowpack The immense amounts of fresh fallen snow over the last few days are settling and consolidating. The fresh snow is moist up to altitudes of 2000 m widespread. Fresh fallen snow and freshly generated snowdrifts lie deposited on shady slopes widespread on top of an unfavourable old snow cover surface. Avalanches in those locations can be easily triggered. On sunny slopes the old snow cover surface was already favourable prior to this period of snowfall. On the northern flank of the Alps on north-facing slopes, furthermore, there are expansively metamorphosed (faceted) layers deeply embedded inside the snow cover in some places. In the southern Valais and in the Grisons on north-facing slopes the entire old snow cover is expansively metamorphosed (faceted) and loosely-packed in some places. There, avalanches can fracture down to deeper down layers inside the snowpack. Particularly as a consequence of rising foehn wind influence, fresh, in some places easily triggered snowdrift accumulations will be generated on Monday. As a result of higher temperatures and solar radiation, moist slides and moist avalanches can be expected to trigger from the fresh fallen snow up to high altitudes on steep, sunny slopes. Observed weather review Sunday, 12.03.2023 In the northern regions skies were heavily overcast for the most part, in the Valais and in Grisons it became increasingly sunny. In the Ticino it was predominantly sunny. In the northern regions the precipitation rounded to a close during the afternoon. Fresh snow Between Saturday afternoon and Sunday afternoon the following amounts of fresh snow were registered above approximately 2000 m:
Thus, since the beginning of this period of precipitation on Tuesday evening until Sunday afternoon, the following overall amounts of fresh snow have been registered above approximately 2200 m:
Temperature At midday at 2000 m, between -1 °C in the northern regions and +3 °C in the southern regions. Wind Winds were blowing from westerly to northwesterly directions,
Weather forecast through Monday, 13.03.2023 On Sunday night nocturnal skies will be predominantly overcast. During the daytime hours on Monday in the northern regions it will be predominantly sunny. In the southern regions the sun will appear only intermittently. It is expected to be inordinately mild and windy. Fresh snow - Temperature On Sunday night temperatures are expected to rise significantly, at midday on Monday at 2000 m in the northern regions +6 °C, in the southern regions +1 °C. Wind Winds are expected to be southwesterly,
Outlook through Wednesday, 15.03.2023 On Monday night precipitation from the south and the west is expected to set in once again. In the northern regions snowfall is expected to persist until Wednesday aftertnoon. In the southern regions skies will brighten swiftly on Wednesday. The snowfall level will lie between 1300 and 1600 m to begin with, subsequently will descend to below 1000 m. In the furthermost western regions of the Lower Valais 40 to 60 cm of snowfall is expected, on the northern Alpine Ridge 30 to 50 cm, elsewhere less. Winds in the mountains will continue to be blowing at strong velocity, on Tuesday from southwesterly directions, on Wednesday from northwesterly directions. Avalanche danger levels are expected to increase in the southern regions on Tuesday. In the remaining regions of Switzerland avalanche danger levels are not expected to change significantly. Conditions in backcountry terrain away from secured ski runs will remain treacherous for winter sports enthusiasts over far-reaching areas.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)