Persistent weak layers
- Alle Höhenlagen
A generally favourable avalanche situation will prevail.
Individual avalanche prone locations for dry avalanches are to be found in particular in extremely steep terrain. In isolated cases avalanches can be triggered in the weakly bonded old snow and reach medium size in some cases. In addition small wind slabs will form in particular on north facing slopes. Apart from the danger of being buried, restraint should be exercised as well in view of the danger of avalanches sweeping people along and giving rise to falls.
Snowpack With the exception of the northern and furthermost western parts of the Lower Valais, the snow cover is expansively metamorphosed (faceted) over widespread areas and has loosely-packed layers. On the northern flank of the Alps these layers are often located in the uppermost part of the snow cover; in the southern Valais and in Grisons, the entire snowpack is expansively metamorphosed (faceted) and loose in some places. The frequency of avalanche prone locations is decreasing, however in isolated cases dry-snow slab avalanches can still be triggered. This applies to the northern parts of Grisons more than anywhere else, also to some extent to slopes which have already been tracked by backcountry tourers. As a consequence of solar radiation and higher daytime temperatures, increasingly frequent wet-snow avalanches are once again possible on very steep south-facing slopes. In regions with a weak old snowpack more than anywhere else, wet slab avalanches can also be triggered by persons in isolated cases. Observed weather review Friday, 17.02.2023 In the northern regions and in Grisons, skies were heavily overcast for the most part; in the Valais and in the southern regions it was predominantly sunny. Fresh snow - Temperature At midday at 2000 m, between +1 °C in the northern regions and +4 °C in the Valais and in the southern regions. Wind Winds were westerly to northwesterly,
Weather forecast through Saturday, 18.02.2023 In the Jura region skies are expected to be predominantly overcast, in the Prealps partly overcast. In the mountains, it will be mostly sunny following a night of clear skies. Fresh snow - Temperature At midday at 2000 m, between +6 °C in the western and in the southern regions, and +4 °C in the eastern regions. Wind Winds will be westerly to northwesterly, blowing predominantly at moderate strength in the mountains, at strong velocity in some regions of the central and eastern parts of the Main Alpine Ridge. Outlook through Monday, 20.02.2023 On Sunday in the Jura region, in the central and eastern sectors of the northern flank of the Alps, as well is in the furthermost northern regions of Grisons, skies will be variably to heavily overcast. In the evening and during the nocturnal hours on Sunday night in the eastern regions, a small amount of precipitation is anticipated. In the remaining regions of Switzerland it will be predominantly sunny on Sunday and on Monday. Winds on Sunday will still be blowing at moderate to strong velocity from westerly to northwesterly directions, in the Ticino as northerly foehn wind at strong velocity extending down to the valleys. On Monday the winds are expected to slacken off. Danger of dry-snow avalanches will continue to decrease incrementally, danger of wet-snow avalanches will be subject to a daytime danger cycle.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)