Saas Fee

Considerable danger of dry and wet avalanches will be encountered in some regions.

The avalanche prone locations for dry avalanches are to be found in all aspects above approximately 3000 m. An increasing number of natural dry avalanches are possible as a consequence of the snowfall. They can in some cases release the saturated snowpack and reach large size. The avalanche prone locations for wet avalanches are to be found below approximately 3000 m. As a consequence of the rain at any time medium-sized and, in isolated cases, large wet avalanches are to be expected.

Experience and restraint are required.

Snowpack Dry-snow avalanches are possible on steep north-facing slopes more than anywhere else. Beneath the fresh fallen snow of this last week, the old snow cover is thoroughly wet on north-facing slopes up to 2800 m, in the other aspects as far up as significantly over 3000 m. In Grisons more than anywhere else, in some parts of the southern Valais, and in isolated cases also in the remaining areas of Switzerland, there are still weakened layers evident deeply embedded inside the snow cover. On north-facing slopes between approximately 2800 and 3300 m, these weakened layers are incrementally becoming wet for the first time this winter season, and thereby, further weakened. During the night of overcast skies on Saturday night, the snow cover surface was able to cool down only to a limited extent, and froze only above the zero-degree altitude level. Thus, the danger of wet-snow avalanches is heightened already in the early morning hours, and will increase further during the course of the day, particularly in those regions where there are bright intervals. Naturally triggered wet-snow avalanches can be expected. On high altitude north-facing slopes more than anywhere else, avalanches can sweep away the entire snow cover and, in places, plummet far down towards the valley. Observed weather review Saturday, 20.05.2023 On the Main Alpine Ridge and southwards therefrom, there was precipitation registered which fell as snow above 2600 m. In the remaining regions of Switzerland skies were predominantly overcast accompanied by brief intervals of brightness, but also by showers from place to place. Fresh snow Between Friday afternoon and Saturday afternoon, the following amounts of fresh snow were registered above 3000 m:

• Upper Valais sector of the Main Alpine Ridge from Monte Rosa into the Simplon region: 15 to 30 cm, as much as 40 cm from place to place;
• remaining parts of the Main Alpine Ridge from Great St. Bernard into the Bernina region, Aletsch region: 5 to 15 cm;
• in the other regions of Switzerland, less, or else it remained dry.

Thus, in the Upper Valais sector of the Main Alpine Ridge along the Italian border, a total of 20 to 50 cm of fresh snow has been registered above approximately 2800 m during the last two days. Temperature The zero-degree level at midday lay between 2800 m in the southwestern regions and 3200 m in the northeastern regions. Wind Winds were blowing at light to moderate strength, at moderate to strong velocity in the northern part of the Alpine Ridge, from southeasterly directions. Weather forecast through Sunday, 21.05.2023 During the nocturnal hours on Saturday night, skies will be predominantly overcast. During the daytime hours on Sunday, it will be partly sunny accompanied by possible isolated showers or thunderstorms. In the western part of the Main Alpine Ridge and in the western part of Ticino, precipitation is anticipated until midday on Monday. Fresh snow Between Saturday evening and Sunday midday, the following amounts of fresh snow are expected above 3200 m:

• Upper Valais sector of Main Alpine Ridge from Monte Rosa into the Simplon region: 30 to 50 cm;
• remaining parts of the western sector of the Main Alpine Ridge, Aletsch region, Val Bregaglia, Bernina: 5 to 15 cm;
• in the remaining regions of Switzerland, less; or else it will remain dry.

Temperature The zero-degree level will ascend during the course of the day to approximately 3300 m. Wind Winds in the high alpine regions will be blowing at moderate to strong velocity during the nighttime hours, during the daytime hours blowing at light to moderate strength, from southeasterly directions. Outlook through Tuesday, 23.05.2023 Following a night of partially clear skies it will be rather sunny on Monday, on Tuesday only partly sunny. In the mountains, isolated showers or thunderstorms are possible during the latter part of each day. Winds will be blowing predominantly at light strength. It will remain mild, with the zero-degree level at 3300 m. The danger of dry-snow avalanches is expected to decrease, however the conditions for backcountry winter sports in the Upper Valais sector of the Main Alpine Ridge will remain highly treacherous, due to the fresh fallen snow from the last few days. There, in addition, increasingly frequent wet-snow avalanches can be expected to release from the fresh fallen snow, due to solar radiation, including large-sized releases. Backcountry tours require much experience. Also in the remaining regions of Switzerland, the danger of dry-snow avalanches is expected to decrease. The danger of wet-snow avalanches will be subject to a daytime danger cycle. In case of reduced nocturnal outgoing longwave radiation, the danger of wet-snow avalanches will swiftly increase during the course of each morning. Backcountry tours and ascents to mountain refuges should be started early and brought to an end early in the day.