Persistent weak layers
- All elevations
Considerable danger of dry and wet avalanches will be encountered over a wide area.
In some places avalanches can be triggered in the weakly bonded old snow and reach medium size. The avalanche prone locations are to be found especially on steep north facing slopes. Careful route selection is recommended.
Wet snow slides and avalanches are to be expected. This applies on north facing slopes below approximately 2000 m, as well as on east, south and west facing slopes below approximately 2400 m. Mostly the avalanches are small.
Snowpack On north-facing slopes above 2200 m more than anywhere else there are expansively metamorphosed (faceted) weak layers evident deeply embedded inside the snowpack. In the Valais and on the northern flank of the Alps, these weak layers are generally blanketed over by thick layers of fresher snow. Particularly in places where the snow is shallow, avalanches can be triggered in these expansively metamorphosed (faceted) layers in the old snowpack in those locations and in some places grow to large size. In Grisons and in the northern Ticino these weak layers are located closer to the surface of the snowpack. Particularly in Grisons they are still easily triggered. Numerous reports of avalanche releases from this week confirm the unfavourable structure of the snow cover. Places where avalanches have been triggered by persons are incrementally decreasing in frequency, nevertheless large-sized avalanche releases are for the time being still possible. Observed weather review Sunday, 19.03.2023 On Saturday night skies were predominantly overcast. It was partly sunny during the morning hours, apart from the furthermost western regions. Most sunshine was to be seen in the southern Ticino and in far-reaching parts of Grisons. During the afternoon hours there was a small amount of intermittent precipitation with the snowfall level at 1700 m Fresh snow - Temperature At midday at 2000 m, between 0 °C in the northern regions and +2 °C in the southern regions. Wind Winds at high altitudes during the nighttime hours were temporarily blowing at moderate strength from southerly directions, otherwise winds were blowing at light strength. Weather forecast through Monday, 20.03.2023 On Sunday night skies will be prominantly overcast accompanied by a small amount of precipitation. During the daytime hours on Monday skies will clear up, to begin with in the western regions, subsequently also in the eastern regions, and it will become predominantly sunny. In the southern regions it will be generally sunny. Fresh snow The snowfall level will lie at 1500 m:
Temperature At midday at 2000 m, between -1 °C in the northern regions and +2 °C in the southern regions. Wind Winds are expected to be light, intermittently blowing at moderate strength on the Main Alpine Ridge, from northerly directions. Outlook through Wednesday, 22.03.2023 On Monday night skies will be predominantly clear and it is expected to be relatively sunny on Tuesday morning. Subsequently cloud cover will move in from the west. On Tuesday night skies will again clear up, and Wednesday morning will be predominantly sunny. During the afternoon, cloud cover will again move in from the west. Winds will be blowing mostly at light strength, intermittently at moderate velocity from westerly to southwesterly directions. The zero-degree level will lie at 2500 m. The danger of dry-snow avalanches will incrementally decrease. The danger of wet-snow avalanches is expected to increase slightly during the course of each day.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)