nördliches Urseren

In the west a considerable avalanche danger will be encountered in some regions. Weak layers in the old snowpack necessitate caution.

In some places avalanches can be triggered in the weakly bonded old snow and reach medium size in some cases. As a consequence of a strong westerly wind, wind slabs formed at elevated altitudes. These are rather small but prone to triggering. They are to be evaluated with care and prudence in steep terrain. In high Alpine regions the avalanche prone locations are more widespread and the danger is slightly greater. Defensive route selection is recommended.

Below approximately 2200 m small and medium-sized gliding avalanches and moist snow slides are to be expected.

Snowpack Fresh fallen snow and snowdrift accumulations cover an unfavourable old snowpack. The base of the snow cover is expansively metamorphosed (faceted) over widespread areas and loose. Avalanches can fracture down to more deeply embedded layers inside the snowpack. Below 2000 m as well as on steep south-facing slopes at high altitudes, the shallow snowpack is generally moist. Observed weather review Wednesday, 21.12.2022 Skies were predominantly overcast, accompanied by a few bright intervals in Grisons and the southern regions. Fresh snow By Wednesday afternoon the following amounts of fresh snow were registered above approximately 2200 m:

• northern Alpine Ridge west of the Wildstrubel, furthermost western part of Lower Valais: 5 to 10 cm; along the French border as much as 20 cm;
• in the remaining regions of Switzerland, only a few centimetres; in the southern part of Upper Valais, in the southern regions of Switzerland and in Grisons it remained dry.

Temperature At midday at 2000 m, between +2 °C in the northern regions and 0 °C in the southern regions. Wind Winds were blowing at moderate strength, from place to place also at strong velocity, from southerly to southwesterly directions during the nocturnal hours, from westerly directions during the daytime. Weather forecast through Thursday, 22.12.2022 Skies are expected to be heavily overcast. Above approximately 1600 to 1900 m a small amount of snowfall is anticipated. On the Main Alpine Ridge it will be sunny in places, further to the south predominantly sunny and dry. Fresh snow Between Wednesday afternoon and Thursday afternoon the following amounts of fresh snow are expected above 2000 m:

• furthermost western part of Lower Valais along the French border: approximately 10 cm;
• in the other regions of Switzerland, only a few centimetres; in the Ticino and in Grisons it will remain dry for the most part.

Temperature At midday at 2000 m, 0 °C. Wind Winds during the daytime will be blowing at strong velocity, on the northern flank of the Alps and in the high alpine regions at storm velocity in some places, from the west. Outlook through Saturday, 24.12.2022 As a consequence of strong to storm-strength westerly winds, skies will be heavily overcast throughout Switzerland except in the furthermost southern regions, accompanied in some places by intensive precipitation. The snowfall level will ascend to 2200 m during Thursday night, in the western regions even to 2500 m. On Saturday the snowfall level will descend to 2000 m in the western regions and to 1600 m in the eastern regions. Between Thursday afternoon and the end of this period of precipitation on Saturday at midday, the following amounts of fresh snow are expected at high altitudes:

• northern Alpine Ridge west of the Tödi, furthermost western part of Lower Valais: 40 to 80 cm; along the French border as much as one metre;
• remaining parts of the northern flank of the Alps, northern Prättigau, remaining parts of Valais: 20 to 40 cm; in the other regions, less; and in the furthermost southern regions it will remain dry.

Avalanche danger levels are expected to increase everywhere except in the furthermost southern regions. Due to the weakness of the old snowpack, numerous naturally triggered wet-snow and dry-snow avalanches can be expected in the major areas of precipitation. Presumably, avalanche Danger Level 4 (high) will be reached as early as Friday in the furthermost western part of Lower Valais and the western parts of the northern Alpine Ridge, on Saturday also in other areas of the northern Alpine ridge. Since there is overall only a relatively small amount of snow, the dangers are limited to ski touring and freeriding terrain for the most part.