Waadtländer Voralpen

Distinct weak layers in the old snowpack necessitate caution.

As a consequence of a moderate to strong southwesterly wind, clearly visible wind slabs formed especially adjacent to ridgelines and in gullies and bowls. They can be released even by a single winter sport participant. The wind slabs are to be evaluated with care and prudence in steep terrain. Avalanches can additionally in some places be released in the weakly bonded old snow also. These avalanche prone locations are to be found especially on very steep shady slopes above approximately 2000 m. They are rather rare but are difficult to recognise. Avalanches can reach medium size. Snow sport activities outside marked and open pistes call for careful route selection.

As a consequence of warming during the day and solar radiation gliding avalanches and moist snow slides are to be expected.

Snowpack Fresh fallen snow and freshly generated snowdrifts from this last week were deposited on top of a weak old snowpack surface over widespread areas above approximately 2000 m. The lowermost base of the snowpack is expansively metamorphosed (faceted) and loose in many places. Avalanches can be easily triggered in some places and then fracture down to deeply embedded layers inside the snowpack. In the western sector of the northern flank of the Alps, in the typical foehn lanes of the northern regions and in general in high alpine regions more than anywhere else, predominantly small-sized, nonetheless easily triggered snowdrift accumulations are being generated by the moderate-strength winds. As a consequence of solar radiation and the extraordinarily mild temperatures for this juncture of the season, moist slides and gliding avalanches are possible on very steep sunny slopes and in rocky avalanche starting-zones. Observed weather review Sunday, 18.12.2022 Following a night of clear skies it was predominantly sunny in the mountains during the daytime. In the afternoon, high-altitude clouds moved in from the northwest. Fresh snow - Temperature At midday at 2000 m, temperatures lay between +2 °C in the western regions and -2 °C in the eastern and southern regions. Wind Winds were light, blowing increasingly at moderate strength at high altitudes, from southwesterly to westerly directions. Weather forecast through Monday, 19.12.2022 Nocturnal skies will be clear only in some regions. During the daytime hours it will be quite sunny and extraordinarily mild in the mountains in spite of intermittent high-altitude clouds. Fresh snow - Temperature At midday at 2000 m, temperatures will lie between +8 °C in the northern regions and +4 °C in the southern regions. The zero-degree level will lie at 3500 m. Wind Winds in the western regions and in general at high altitudes will be blowing at moderate strength, intermittently at strong velocity, from westerly to southwesterly directions. Outlook through Wednesday, 21.12.2022 Tuesday On Tuesday it will still be sunny in some areas, in spite of high-altitude cloudbanks. The zero-degree level will continue to lie at 3500 m. The danger of dry-snow avalanches will decrease only incrementally as a result of the far-reaching persistent weak layer. During the course of the day as a result of higher temperatures and solar radiation, gliding avalanches and moist-snow avalanches are possible. Wednesday On Wednesday skies will be overcast. Intermittent precipitation is anticipated, except on the southern flank of the Alps. The snowfall level is expected to descend from 1800 m down to 1300 m. The danger of dry-snow avalanches can increase somewhat at elevated altitudes from region to region. At intermediate altitudes, wet-snow and gliding avalanches can be expected as a result of the rainfall.