Saas Fee

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

The avalanche prone locations for wet avalanches are to be found below approximately 3000 m. As a consequence of the rain at any time wet avalanches are to be expected. These can in some cases release the entire snowpack and reach large size on north facing slopes.

The avalanche prone locations for dry avalanches are to be found in particular on very steep west, north and east facing slopes above approximately 3000 m. Fresh wind slabs represent the main danger. Extensive experience in the assessment of avalanche danger is required.

Snowpack For longer than a week there has been fresh snowfall registered every day at heightened altitudes, so that in the high alpine regions a measurable amount of fresh snow has accumulated in the interim. Frequently the snowfall was accompanied by strong-velocity winds, thereby, large-sized snowdrift accumulations have been generated. Fresh fallen snow and freshly generated snowdrift accumulations are settling and consolidating to an increasing degree, however in the high alpine regions isolated avalanches have been triggered from near-surface layers of the snow cover by persons during the last few days. Beneath the fresh snow of the last few days, the old snow cover on north-facing slopes below approximately 2700 m, in the other aspects up to over 3000 m, is thoroughly wet. In Grisons more than anywhere else, but also in some parts of the southern Valais and in isolated cases also in the other regions of Switzerland, there are still weakened layers evident deeply embedded inside the snow cover. uring the night skies were overcast and the snowpack can cool down only to a limited extent and can freeze only above the zero-degree level altitude. Thus, there is the danger of wet-snow avalanches even in the early morning hours, a danger which is intensifed in case of rainfall, particularly in those regions where there are bright intervals and the danger increases during the course of the day. Naturally triggered, wet-snow avalanches can thus be expected. Particularly on high-altitude north-facing slopes, avalanches can sweep away the entire snow cover and, in some places, advance long distances. Observed weather review Friday, 19.05.2023 In the southern regions there was precipitation registered which fell as snow above 2400 m. In the other regions of Switzerland skies were overcast, with brief sunny intervals. During the afternoon there were local showers in the western regions more than anywhere else. Fresh snow Between Thursday afternoon and Friday afaternoon the following amounts of fresh snow were registered above 2600 m:

• Upper Valais sector of the Main Alpine Ridge along the Italian border: 10 to 20 cm;
• remaining parts of the Main Alpine Ridge and Aletsch region: 5 to 10 cm;
• in the other regions of Switzerland, less.

Temperature The zero-degree level at midday lay at 2800 m. Wind Winds were blowing at light strength, intermittently at moderate velocity, from southeasterly directions. Weather forecast through Saturday, 20.05.2023 Nocturnal skies Friday night will be overcast. On the Main Alpine Ridge and southwards therefrom, persistent precipitation is anticipated. The snowfall level will ascend to approximately 2600 m. In the remaining regions of Switzerland it will be variably cloudy accompanied by extensive bright intervals, including showers and thunderstorms from place to place. Fresh snow Between Friday afternoon and Saturday afternoon, the following amounts of fresh snow are expected above 3000 m:

• Upper Valais sector of the Main Alpine Ridge from Monte Rosa region into the Simplon region: 20 to 40 cm, as much as 50 cm from place to place;
• remaining parts of the Main Alpine Ridge from the Great St. Bernard into the Bernina region, Aletsch region: 5 to 15 cm;
• in the other regions of Switzerland, less; or else it will remain dry.

Temperature The zero-degree level is expected to ascend during the course of the day to approximately 3000 m. Wind Winds in the high alpine regions will be blowing at moderate strength during the nighttime hours, at moderate to strong velocity during the daytime hours, from southeasterly directions. Outlook through Monday, 22.05.2023 Sunday Skies on Saturday night will be predominantly overcast. During the daytime hours on Sunday it will be partly sunny accompanied by isolated showers or thunderstorms. In the Upper Valais sector of the Main Alpine Ridge from Monte Rosa region as far as the Simplon, an additional 20 to 40 cm of fresh snow is possible. Winds will be blowing still at strong velocity during the nocturnal hours, subsequently at light to moderate strength, from southeasterly direction. The zero-degree level will ascend to 3300 m. The danger of dry-snow avalanches, and also of wet-snow avalanches is expected to increase further in the Upper Valais sector of the Main Alpine Ridge. The danger of wet-snow avalanches will be heightened on Saturday night due to nocturnal rainfall. The conditions for winter sports in outlying terrain are critical. In the other regions of Switzerland the danger of dry-snow avalanches is not expected to change significantly and the danger of wet-snow avalanches will increase during the course of the day. Backcountry tours and ascents to mountain refuges should be brought to an end early in the day. Monday Skies on Sunday night will be partly clear. On Monday it will be rather sunny, in the mountains isolated showers or thunderstorms are possible. Winds will be predominantly light In the high alpine regions the danger of dry-snow avalanches is expected to decrease somewhat. Due to nocturnal longwave outgoing radiation on Sunday night, the danger of wet-snow avalanches will be more subject to a daytime danger cycle than during the previous few days.