Waadtländer Voralpen

Considerable avalanche danger will be encountered over a wide area

Considerable avalanche danger will be encountered over a wide area

The new snow and wind slabs are prone to triggering at elevated altitudes. The avalanche prone locations for dry avalanches are to be found above approximately 2000 m. Single winter sport participants can release avalanches, including dangerously large ones. As a consequence of the rain natural avalanches are to be expected. In particular on steep west, north and east facing slopes these can be released in the weakly bonded old snow and reach large size in some cases. Backcountry touring calls for experience in the assessment of avalanche danger and restraint.

As a consequence of fresh fallen snow and winds, snowdrift accumulations are being further generated particularly at high altitudes. They are prone to triggering. Below approximately 1800 to 2200 m, the snowpack has been moistened from the rainfall, thus, increasingly frequent naturally triggered avalanches can be expected. Due to the unfavourable snowpack layering, these releases can fracture down to more deeply embedded layers inside the snowpack, particularly on shady slopes in the western sector of the northern flank of the Alps. From the southern Valais over the northern Ticino as far as Grisons, equally pronounced weak layers are evident inside the old snowpack. Particularly in seldom-frequented west-facing, north-facing and east-facing slopes, avalanches can be triggered in these deeply embedded layers inside the snowpack, in isolated cases also large-sized releases.

In the wake of an interim in the precipitation, snowfall once again set in from the west during the course of the day. The snowfall level ascended swiftly coming from the west, in the Jura region to 1000 m to 1400 m, in the Valais and on the northern flank of the Alps to 1400 to 1800 m. In the valleys and in the eastern and the southern regions, the snowfall level lay significantly lower down. Fresh snow: In the Jura region as well as in the western sector of the northern flank of the Alps, 5 to 10 cm of fresh fallen snow has been registered at high altitudes since early morning. Thus, since Monday evening the following amounts of fresh snow have been registered above approximately 1800 m: - western part of Jura region, northern Alpine Ridge, eastern Ticino, Moesano, Upper Engadine, Val Bregaglia, Val Poschiavo: 20 to 30 cm; - in the other regions of Switzerland, 10 to 20 cm over widespread areas, in the southern part of Upper Valais and in the northwestern part of Ticino, less. Temperature: Temperatures at midday at 2000 m, between 0 °C in the western regions and -2 °C in the eastern and the southern regions, continuing to rise during the afternoon. Wind: - Winds in the Valais and on the northern flank of the Alps were blowing at moderate to strong velocity from westerly to southwesterly directions; - in the Ticino and in Grisons, blowing at light to moderate strength from westerly to northwesterly directions. In the western and the northern regions, skies will be heavily overcast for the most part and snowfall is anticipated. In the Ticino and in central and southern Grisons, it will be predominantly dry and partly sunny during the daytime. The snowfall level during the nocturnal hours will lie at 2000 to 2200 m in the western and the northern regions, in the southern and the eastern regions at 1600 to 1800 m. During the daytime the snowfall level will descend incrementally to approximately 1400 m. Fresh snow: Between Wednesday afternoon and Thursday afternoon, the following amounts of fresh snow are expected above approximately 2200 m: - Lower Valais on the French border, northern Alpine Ridge: 15 to 30 cm; - remaining parts of the northern flank of the Alps, remaining parts of the Valais, northern Grisons, Silvretta, Samnaun: 5 to 15 cm; In the Jura region and in the Valais as well as on the northern flank of the Alps below approximately 2000 m, 10 to 30 mm of rainfall is anticipated. Temperature: At midday at 2000 m, 0 °C in the northern regions and +3 °C in the southeastern regions. Wind: Winds will be blowing at strong to storm-strength from westerly to northwesterly directions.

Friday: On Friday it will be quite sunny and very mild. The zero-degree level will lie at approximately 3000 m. At high altitudes an ongoingly strong-velocity westerly wind will be blowing. As a result of higher temperatures and solar radiation, wet-snow and gliding avalanches continue to be possible. The danger of dry-snow avalanches is expected to incrementally decrease. Saturday: On Friday night and during the day on Saturday, a small amount of snowfall is anticipated in the northern regions. The snowfall level will descend down to low lying areas. As a result of lower temperatures, the danger of wet-snow avalanches will significantly decrease. In the northern regions, a slight increase in the danger of dry-snow avalanches can be expected as a result of the freshly generated snowdrift accumulations.