Zervreila

Considerable avalanche danger will be encountered in some regions. Wet avalanches during the day.

In some places avalanches can be triggered in the weakly bonded old snow and reach medium size in some cases. The avalanche prone locations are to be found especially on steep north facing slopes. Careful route selection is recommended.

Outgoing longwave radiation during the night will be reduced. As a consequence of warming during the day and solar radiation wet snow slides and avalanches are possible. This applies in particular on east and west facing slopes below approximately 2400 m. Avalanches can reach medium size, especially on steep east facing slopes.

Snowpack On north-facing slopes above approximately 2200 m more than anywhere else, there are expansively metamorphosed (faceted) weak layers deeply embedded inside the snowpack over widespread areas. In the Valais and on the northern flank of the Alps these weak layers are for the most part blanketed over by thick layers of fresher snow. Avalanches in those places can be triggered in these expansively metamorphosed (faceted) layers only in some places, in particular where the snow on the ground is relatively shallow. Particularly in Grisons, such avalanche triggerings are still relatively easy in some places. The places where avalanches can be triggered by persons are incrementally decreasing in frequency, nevertheless large-sized avalanche triggerings are still possible. On south-facing slopes the snow cover is thoroughly wet to an ever-increasing degree, even up as high as high alpine regions. Also on west-facing slopes the snowpack is thoroughly wet up to nearly 3000 m. On east-facing slopes the snowpack is in the process of becoming thoroughly wet up to 2200 to 2600 m, on north-facing slopes to 1500 to 1800 m. As a consequence of reduced nocturnal outgoing (longwave) radiation on Thursday night, the snowpack surface will form only a thin crust. In those regions where there is solar radiation the crust will subsequently soften up swiftly. Observed weather review Wednesday, 22.03.2023 Following a night of predominantly clear skies it was generally sunny during the daytime hours. Towards evening, cloud cover moved in from the west. Fresh snow - Temperature At midday at 2000 m, +6 °C. Wind

• Winds were blowing at light strength, intermittently at moderate velocity, from westerly to southerly directions.

Weather forecast through Thursday, 23.03.2023 On Wednesday night skies are expected to be predominantly overcast and for that reason the outgoing longwave radiation will be reduced. During the daytime hours on Thursday, skies will remain heavily overcast in the western regions, in the southern and the eastern regions it will be partly sunny. Towards evening in the western regions, showers are possible from place to place. Fresh snow - Temperature At midday at 2000 m, between +5 °C in the northern regions and +3 °C in the southern regions. Wind Winds will be blowing from southwesterly directions,

• in the western and northern regions at moderate to strong velocity;
• in the southern and eastern regions at light to moderate strength.

Outlook through Saturday, 25.03.2023 Friday Skies are expected to be predominantly overcast and precipitation is anticipated over widespread areas. The snowfall level will descend from 2300 m down to nearly 1800 m. In the furthermost western regions approximately 20 to 30 cm of fresh snowfall is expected, on the northern flank of the Alps 10 to 20 cm of fresh snow. In the northern regions a westerly to southwesterly wind will be blowing at strong velocity, in the high alpine regions blowing at storm strength generally. In the foehn-impacted regions of the north, a moderate to strong-velocity southerly foehn wind will be blowing. The danger of dry-snow avalanches will increase in the regions where precipitation is heaviest. As a consequence of rainfall, wet-snow avalanches can be expected on north-facing slopes more than anywhere else. Saturday Over widespread areas, further precipitation is anticipated. The snowfall level will descend from 1800 m down to nearly 1200 m during the nighttime hours. In the northern and the western regions, an additional 20 cm of fresh snow is expected by evening, more from place to place. In the southern regions it is expected to be rather sunny. Winds will continue to blow at strong to storm strength from westerly directions. The danger of dry-snow avalanches will continue to increase in the major areas of precipitation. As a consequence of the descending snowfall level, the activity of wet-snow avalanches will diminish.