Aigle-Leysin

Stormy weather and new snow: In the west a high avalanche danger will prevail

On Wednesday evening precipitation set in from the west. During the daytime on Wednesday skies were overcast and there was precipitation over widespread areas. The snowfall level during the nocturnal hours lay at 1600 m, during the daytime it ascended to 1800 m. In Grisons there was only a small amount of precipitation, in the furthermost southern regions it remained dry. Fresh snow: Between Wednesday evening and Thursday afternoon, the following amounts of fresh snow were registered above approximately 2000 m: - furthermost western part of the Lower Valais on the French border and northern Lower Valais: 15 to 30 cm; - remaining parts of the Lower Valais and western sector of the northern flank of the Alps: 5 to 15 cm; - remaining regions of Switzerland: only a few centimetres or else it remained dry. Temperature: At midday at 2000 m: between -1 °C in the northern and the western regions and +2 °C in the Ticino and in Grisons. Wind: Winds were blowing at strong to storm strength from westerly directions. On Thursday night and during the daytime hours on Friday, precipiation is anticipated over widespread areas which will be heavy in western regions and on the northern flank of the Alps. In the southern regions and in the Engadine, skies will be variably cloudy, in the afternoon light precipitation is anticipated. The snowfall level will lie at approximately 2000 m. Fresh snow: Between Thursday afternoon and Friday afternoon, the following amounts of fresh snow are expected above approximately 2200 m: - furthermost western part of the Lower Valais, northern Lower Valais, as well as the Vaud Alps: 50 to 80 cm; in the furthermost western regions as much as 100 cm; - remaining parts of the Valais and remaining parts of the western sector of the northern flank of the Alps: 20 to 40 cm; - remaining parts of the northern flank of the Alps and Prättigau: 10 to 20 cm; - remaining regions of Switzerland: only a few centimetres or else it will remain dry. Temperature: At midday at 2000 m: approximately +1 °C. Wind: Winds will be blowing at strong to storm strength from westerly directions.

Stormy weather and new snow: In the west a high avalanche danger will prevail

As a consequence of new snow and a sometimes storm force westerly wind, large wind slabs will form also in areas not adjacent to ridgelines. Natural avalanches are to be expected. Especially on north facing slopes the dry avalanches can release the saturated snowpack and can reach as far as areas without any snow cover. Exposed parts of transportation routes can be endangered. Especially on north facing slopes more small and medium-sized wet avalanches are to be expected as a consequence of the rain, in particular below approximately 2000 m. The backcountry and freeriding conditions are critical.

As a consequence of heavy snowfall and storm-strength westerly winds over widespread areas, additional wide-ranging snowdrift accumulations are being generated in the western and the northern regions. Bonding of the layers of fresh fallen snow and freshly generated snowdrifts to the old snowpack surface is generally quite favourable. Only on north-facing slopes at high altitudes, on the other hand, is the snowpack surface expansively metamorphosed (faceted) in some places and forms a weak snowbase in those regions. In the inneralpine regions of Grisons and in some parts of the Valais, the snowpack structuring on north-facing slopes continues to be weak. Up to approximately 2000 m the snowpack is weak as a result of the rainfall, and is forfeiting its stability. Wet-snow avalanches can be expected.

Saturday: On Saturday, skies will be heavily overcast for the most part and additional precipitation is anticipated. The snowfall level will descend during Friday night down to approximately 600 m. In the northern regions, storm-strength westerly winds will slacken off during the course of the day and subsequently shift to northerly. In the southern regions it will become partly sunny as a result of the intensifying northerly winds. The danger of dry-snow avalanches will remain delicate over widespread areas. As a consequence of the gradually diminishing precipitation and the quieting of the storm-strength winds during the course of the day, naturally triggered avalanche activity will decrease. Nevertheless, for winter sports enthusiasts in outlying terrain, the situation continues to remain critical over widespread areas. As a result of lower temperatures, the danger of wet-snow avalanches will decrease. Sunday: On Saturday night the precipitation will come to an end. During the daytime hours on Sunday it will be predominantly sunny. Along the Alps, some cloudbanks will prevail. In the southern regions, strong-velocity northerly winds will be blowing until the early morning hours, in the northern regions winds will be light. The danger of dry-snow avalanches will decrease slightly in the western and the northern regions, yet will remain treacherous for winter sports enthusiasts in outlying terrain, away from secured ski pistes. As a result of solar radiation, moist slides can be expected in the regions where precipitation has been heavy.