südliches Urseren

As a consequence of new snow and wind a considerable avalanche danger will be encountered over a wide area.

As a consequence of new snow and strong wind the wind slabs will increase in size additionally. The fresh wind slabs are prone to triggering. They are to be evaluated with care and prudence in steep terrain. In some places avalanches can also penetrate deep layers and reach dangerously large size. These avalanche prone locations are to be found in particular on west, north and east facing slopes, especially in areas where the snow cover is rather shallow. Backcountry touring calls for experience in the assessment of avalanche danger and careful route selection.

Snowpack The fresh fallen snow is being transported by westerly to northerly winds. Fresh snow and freshly generated snowdrifts are prone to triggering.In addition, in the upper layers of the snow cover there are expansively metamorphosed (faceted) and weak layers evident in some places bordering on melt-freeze crusts. On west-facing, north-facing and east-facing slopes above approximately 2200 more than anywhere else, these weakened layers are frequently blanketed by thick layers of fresher snow and are prone to triggering in those places.Snow depths in the Lower Valais and on the northern Alpine Ridge are slightly below-average to average. In the remaining regions of Switzerland, snow depths are significantly below average for this juncture of the season, including in high alpine regions. Observed weather review Wednesday, 12.04.2023 During the night in the western and the northern regions there was a small amount of snowfall registered. During the daytime hours it was predominantly dry, but skies were overcast. During the afternoon snowfall set in once again from the west. The snowfall level lay between 1500 and 2000 m. Fresh snow On Tuesday night on the northern Alpine Ridge and in the Valais, 5 to 10 cm of fresh fallen snow was registered, as much as 15 cm from place to place. In the remaining regions of Switzerland there was less snowfall registered.Thus, between Monday evening and Wednesday afternoon, the following overall amounts of fresh snow were registered above approximately 2400 m:

• northern Alpine Ridge from the Aletsch region into the Glarus Alps: 20 to 30 cm;
• remaining parts of Alpine Ridge, Valais not including the Simplon region: 10 to 20 cm;
• in the remaining regions, less; in the Ticino, in central and southern Grisons it remained predominantly dry.

Temperature At midday at 2000 m, between +3 °C in the northern regions and +1 °C in the southern regions. Wind Winds were blowing at moderate to strong velocity over widespread areas, predominantly at light-to-moderate strength in the Ticino and in Grisons, from westerly to southerly directions. Weather forecast through Thursday, 13.04.2023 During the nocturnal hours, snowfall is anticipated over widespread areas. During the daytime hours in the western regions it will be intermittently dry, in the eastern regions additional snowfall is expected. In the Ticino it will be partly sunny. The snowfall level in the northern regions is expected to descend from approximately 1800 m down to low lying areas; in the southern regions down to approximately 1200 m. Fresh snow Between Wednesday evening and Thursday afternoon, the following amounts of fresh snow are anticipated above approximately 2000 m:

• furthermost western part of the Lower Valais, northern Alpine Ridge, Grisons not including Val Moesano: 20 to 30 cm; in the furthermost western regions and in northern Grisons as much as 40 cm;
• remaining parts of the northern flank of the Alps, remaining parts of Lower Valais, southern Goms, remaining parts of Gotthard region, Moesano: 10 to 20 cm;
• in the other parts of Switzerland, less.

Temperature At midday at 2000 m, -5 °C. Wind

• winds during the nighttime hours will be blowing predominantly at moderate strength from westerly directions
• in early morning, winds are expected to shift to northerly and intensify to an increasing degree on the Main Alpine Ridge and southwards therefrom

Outlook through Saturday, 15.04.2023 Friday During Thursday night in the eastern regions more than anywhere else, additional snowfall is anticipated down to low lying areas. During the daytime hours on Friday, further intermittent snowfall is anticipated in the eastern regions. In the western regions, skies will be intermittently bright; in the southern regions it will be quite sunny as a result of northerly winds. Avalanche danger levels could increase somewhat in the eastern regions, in the other regions of Switzerland avalanche danger levels are not expected to change significantly. Saturday Above approximately 1200 m there will be snowfall, with the focal point in the western and the northern regions. A moderate to strong-velocity northwesterly wind will be blowing. The avalanche situation will continue to remain critical over far-reaching areas for winter sports enthusiasts in backcountry terrain apart form secured ski runs. In the central sector of the southern flank of the Alps the avalanche situation will be somewhat more favourable.