Persistent weak layers
- Alle Höhenlagen
Weakly bonded old snow requires caution. Wet avalanches during the day.
Weak layers in the upper part of the snowpack can still be released in some place by people. Avalanches can in some cases reach medium size. The avalanche prone locations are to be found especially in gullies and bowls, and behind abrupt changes in the terrain. As a consequence of warming during the day and the solar radiation, the likelihood of dry avalanches being released will increase a little on steep sunny slopes. Backcountry touring and other off-piste activities call for careful route selection.
Snowpack Inside the snow cover there are expansively metamorphosed (faceted) and loosely-packed layers of snow evident over widespread areas. On the northern flank of the Allps, these layers are often found in the uppermost part of the snow cover. Particularly in the southern Valais and in Grisons, the entire snow cover is expansively metamorphosed (faceted) in some places. Further to the east the faceted layers are blanketed over by fresh snowfall and snowdrift accumulations which were generated last weekend. In the remaining regions of Switzerland, older snowdrift accumulations frequently lie deposited on top of faceted weakened layers and are prone to triggering. In the northern and the furthermost western parts of Lower Valais, the snowpack structure is most favourable and there are hardly any pronounced weak layers inside the snowpack. As a consequence of higher temperatures and solar radiation, wet-snow avalanches can be expected on very steep south-facing slopes during the course of the day. Observed weather review Sunday, 12.02.2023 Following a night of clear skies, it was sunny and mild during the daytime hours. Fresh snow - Temperature At midday at 2000 m, between +5 °C in the western regions and +3 °C in the eastern regions. Wind Winds were blowing at light to moderate strength from northeasterly directions. Weather forecast through Monday, 13.02.2023 Following a night of clear skies it is expected to be sunny and mild during the daytime hours. Fresh snow - Temperature At midday at 2000 m, +4 °C, the zero-degree level will be at approximately 3000 m. Wind Winds are expected to be predominantly light. Outlook through Wednesday, 15.02.2023 Following nights of clear skies it is expected to be sunny and mild during the daytime hours. The zero-degree level will lie at approximately 3000 m. The danger of dry-snow avalanches will continue to decrease incrementally. On very steep sunny slopes, wet-snow and gliding avalanches can be expected.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)