Rheinwald

Considerable avalanche danger will be encountered over a wide area

Considerable avalanche danger will be encountered over a wide area

The fresh wind slabs are mostly small but in some cases prone to triggering. At elevated altitudes the avalanche prone locations are more prevalent. Additionally in very isolated cases avalanches can also be released in the old snowpack and reach medium size. This applies in particular on little-used, rather lightly snow-covered shady slopes above approximately 2400 m. These avalanche prone locations are barely recognisable, even to the trained eye. Defensive route selection is appropriate.

As a consequence of fresh snow and storm-strength winds, large-sized snowdrift accumulations have been generated in the western regions more than anywhere else. Beneath the layers of fresh snow and snowdrift accumulations from last week the old snowpack surface in many regions was hardened and showed striking signs of rain, wind and sun. Particularly in the inneralpine regions of the Valais and Grisons this crust manifests less pronounced effects and is frequently breakable. From the central Valais over the northern Ticino as far as Grisons more than anywhere else, very isolated avalanches can be triggered in the old snow at high altitudes. This is possible in expansively metamorphosed (faceted) loose-snow layers either immediately beneath the rain crust which formed at the end of December or more deeply embedded inside the snowpack.

In the northern regions skies were predominantly overcast. There was intermittent snowfall. The snowfall level descended from 1200 m down to low lying areas. During the afternoon there was only a minor amount of snowfall and there were isolated bright intervals. In the southern regions it was predominantly dry and partly sunny. Fresh snow: Between Saturday afternoon and Sunday afternoon: - northern Alpine Ridge from the Diablerets into the Aletsch region, western part of Lower Valais: 20 to 40 cm; - remaining parts of the northern flank of the Alps, remaining parts of Valais not including the valleys of Visp and the Simplon region, Jura region: 15 to 30 cm; - valleys of Visp, Simplon region, Val Bedretto, upper Leventina, northern Grisons: 5 to 15 cm; - in the other regions of Switzerland, only a few centimetres; or else it remained dry. Temperature: At midday at 2000 m, -8 °C in the northern regions and -5 °C in the southern regions. Wind: - On Sunday night, and in particular in the western and the northern regions, strong to storm-strength southwesterly winds were blowing; - during the morning on the Main Alpine Ridge and in the eastern regions, winds were northwesterly, blowing at strong velocity; in the other regions winds were predominantly moderate. During the night in the northern regions, snowfall down to low lying areas is anticipated over widespread areas. In the southern regions it will remain dry. During the daytime on Monday it will be predominantly sunny in the Valais and in the southern regions. In the remaining regions of Switzerland a small amount of snowfall is still expected in the morning, in the afternoon there will be some bright intervals. Fresh snow: Between Sunday afternoon and Monday afternoon: - Lower Valais, northern Upper Valais, northern flank of the Alps: 5 to 15 cm; - in the other regions of Switzerland, less; in the Ticino and the Engadine it will remain predominantly dry. Temperature: At midday at 2000 m, -9 °C in the northern regions and -6 °C in the southern regions. Wind: Winds will be blowing at light to moderate strength, at strong velocity at high altitudes and in the southern regions, from northerly to northeasterly directions.

On Tuesday and Wednesday it will be sunny and significantly milder. The midday temperature at 2000 m will ascend in the western and southern regions to approximately 0 °C, in the eastern regions to -4 °C. At high altitudes a moderate-strength northeasterly wind will be blowing; in the Prealps and the Jura region, a moderate strength bise wind is expected. The danger of dry-snow avalanches will decrease. On sunny slopes, wet-snow slides and gliding avalanches can be expected.