südliches Urseren

In some regions increase in avalanche danger as a consequence of new snow and wind.

To some extent avalanches can be released in the old snowpack and reach medium size. These avalanche prone locations are to be found in particular at transitions from a shallow to a deep snowpack. In addition the fresh and older wind slabs are prone to triggering in some cases. They are to be found in particular in gullies and bowls, and behind abrupt changes in the terrain. The wind slabs are to be evaluated with care and prudence in steep terrain. Backcountry touring and other off-piste activities call for careful route selection.

Snowpack As a consequence of fresh snow and strong-velocity northwesterly winds, somewhat large-sized snowdrift accumulations are being generated in the eastern regions more than anywhere else. In the remaining regions of Switzerland, predominantly small-sized snowdrift accumulations have been generated during the last few days in particular. The snowdrift accumulations lie deposited distant from ridgelines more than anywhere else, atop an unfavourable old snowpack surface and are frequently prone to triggering. More deeply embedded inside the snowpack in the regions from southern Valais over the Gotthard region as far as Grisons, there are numerous softened, expansively metamorphosed (faceted) layers wedged between consolidated layers and crusts. These faceted layers are especially pronounced in places where the snowpack is shallow and where one breaks down to the ground on skis. On the northern flank of the Alps the lowermost part of the snowpack is frequently well consolidated; however, on top of it several expansively metamorphosed (faceted) layers are embedded in the snowpack. In the northern and the furthermost western part of Lower Valais the snowpack layering is most favourable and there are hardly any pronounced weak layers evident. Observed weather review Wednesday, 01.02.2023 During the course of Tuesday night in the northern regions and the Valais, a few centimetres of fresh snow was registered. During the daytime on Wednesday skies were frequently overcast in the northeastern regions in particular, in the other regions of Switzerland it was quite sunny. Fresh snow - Temperature At midday at 2000 m, -6 °C in the northern regions and -1 °C in the southern regions. Wind Winds were blowing at moderate to strong velocity from westerly to northwesterly directions. Weather forecast through Thursday, 02.02.2023 In the northern and the eastern regions, as well as in the Jura region, intermittent snowfall is anticipated above approximately 700 m. In the Valais, skies are expected to brighten during the course of the day. On the southern flank of the Alps it will be predominantly sunny as a result of northerly winds. Fresh snow Between Wednesday evening and Thursday afternoon, the following amounts of fresh snow are expected:

• Glarus Alps, Alpstein, northern Prättigau, Silvretta, Samnaun: 10 to 20 cm;
• Jura region, remaining parts of the northern flank of the Alps from Haslital as far as Liechtenstein, remaining parts of northern Grisons, remaining parts of Lower Engadine: 5 to 10 cm.

Temperature At midday at 2000 m, -6 °C in the northern regions and -3 °C in the southern regions. Wind Winds will be blowing from northerly to northwesterly directions,

• in the western regions at light strength, at moderate velocity at high altitudes;
• in the remaining regions of Switzerland blowing at moderate to strong velocity, intermittently at storm strength at heightened altitudes.

Outlook through Saturday, 04.02.2023 In the northern regions, intermittent snowfall is anticipated on both days, with the focal point in the central and eastern sectors of the northern flank of the Alps, as well as in northern Grisons. The snowfall level on Friday will lie at approximately 700 m. On Saturday the snowfall level will ascend to 1300 m in the western regions, in the other regions of Switzerland it will remain in low lying areas. At elevated altitudes a strong to storm-strength northerly wind will be blowing on both days. In the southern regions it is expected to be predominantly sunny on both days as a consequence of the strong northerly winds which in some places will extend down to low lying areas. As a result of fresh snow and strong-to-stormy northerly winds, avalanche danger levels are expected to increase in the northern regions and, in particular, in the eastern regions. In the other regions of Switzerland, avalanche danger is not expected to change significantly.