nördliches Urseren

In the west a high avalanche danger will be encountered in some regions.

The fresh snow and the sometimes large wind slabs will be deposited on a weakly bonded old snowpack. Single winter sport participants can release avalanches easily. These can release the weakly bonded old snow as well and reach large size in some cases. Natural avalanches are possible as the day progresses. Experience in the assessment of avalanche danger is important.

As a consequence of the rain medium-sized and, in isolated cases, large wet avalanches are to be expected below approximately 2200 m.

Snowpack The snow cover above approximately 2000 m contains soft layers of expansively metamorphoseed (faceted) crystals over widespread areas. This snowpack constitutes a weak base for the prognosticated fresh snow and fresh snowdrifts. For that reason, numerous naturally triggered avalanches can be expected. Dry avalanches that are triggered at high altitudes can sweep away the entire, wet snowpack below 2000 to 2500 m. In steep, shady avalanche starting zones, more than anywhere else, these releases can plummet down to intermediate altitudes. Below 2000 to 2500 m as a consequence of the rainfall, numerous wet-snow avalanches can be expected. Since there is still only insufficient snow on the ground, the risks are limited to ski touring and freeriding terrain by and large. Observed weather review Thursday, 22.12.2022 In Grisons and in the Valais it was quite sunny. In the remaining regions of Switzerland skies were overcast. And above 1800 to 2000 there was a small amount of fresh snow registered. Fresh snow Between Wednesday afternoon and Thursday afternoon on the northern flank of the Alps and in Lower Valais a few centimetres of fresh snowfall was registered. Temperature At midday at 2000 m, approximately 0 °C. Wind On the northern flank of the Alps and in the Valais, strong westerly winds were frequently blowing, in Grisons, blowing at light to moderate strength in Grisons and in the Ticino. Weather forecast through Friday, 23.12.2022 Skies are expected to be heavily overcast, accompanied by precipitation. In the western and the northern regions the precipitation, starting at approximately midnight, will be persistent and intensive. The snowfall level will ascend swiftly during the nocturnal hours, subsequently lie at approximately 2300 m in the northern regions, at 2500 m in some parts of the western regions. In Goms and in Grisons the snowfall level will persist tenaciously below 2000 m. In the southern regions it will remain dry and predominantly sunny during the daytime hours. Fresh snow Between Thursday afternoon and Friday afternoon, the following amounts of fresh snow are anticipated above approximately 2500 m:

• furthermost western part of Lower Valais, northern Alpine Ridge west of the Wildstrubel, northern Alpine Ridge from the Aletsch region as far as the Grimsel: 50 to 80 cm;
• remaining regions of the northern Alpine Ridge and of Lower Valais: 30 to 50 cm;
• southern Upper Valais, northern Prättigau: 20 to 30 cm;
• in the remaining regions of Switzerland, less than 15 cm; in the furthermost southern regions it will remain dry.

Temperature At midday at 2000 m, approximately +2 °C. Wind Winds in the northern regions and in general at high altitudes will be blowing at strong to storm strength from west. Outlook through Sunday, 25.12.2022 Saturday On Friday night in the northern regions and the furthermost western regions the snowfall will continue to be intensive. It is expected that in the furthermost western part of Lower Valais and on the northern Alpine Ridge an additional 20 to 30 cm of snow will fall. The snowfall level is expected to descend to 2000 m in the western regions and down to 1600 m in the eastern regions. During the daytime hours there will be only a small amount of precipitation, but skies will remain heavily overcast. The westerly winds will be blowing at moderate to strong velocity. In the furthermost southern regions it will remain predominantly sunny and dry. The avalanche danger levels are expected to continue to increase on Friday night, particularly in the northern and the furthermost western regions. Danger Level 4 (high) will presumably spread out across the greater part of the northern Alpine Ridge. Since there is overall only a small amount of snow on the ground, the risks are limited to skiing-tour and freeriding terrain for the most part. In the inneralpine regions of Grisons, avalanche danger levels will increase only slightly, in the southern regions avalanche danger levels are not expected to change significantly. Sunday It will be predominantly sunny and mild. The zero-degree level is expected to ascend to 3000 m. The danger of dry-snow naturally triggered avalanches will decrease. Nonetheless, winter sports enthusiasts can still trigger avalanches with ease in many regions, including releases which grow to dangerously larger size. As a result of the higher temperatures and solar radiation, moist-snow avlanches can be expected.