Waadtländer Voralpen

In the early morning a quite favourable avalanche situation will prevail. Wet avalanches during the day

In the early morning a quite favourable avalanche situation will prevail. Wet avalanches during the day

As a consequence of a strong southwesterly wind, mostly small wind slabs formed in the last few days. These are in some cases prone to triggering in particular on north facing slopes. They are to be evaluated with care and prudence especially in terrain where there is a danger of falling. Individual gliding avalanches can also be released in the night or in the morning. As a consequence of warming during the day and solar radiation more frequent medium-sized and large gliding avalanches are to be expected. This applies in particular on steep east, south and west facing slopes below approximately 2500 m. Areas with glide cracks are to be avoided. In addition in particular at high altitude, small and medium-sized wet avalanches are to be expected. Backcountry tours should be concluded timely.

Snowdrift accumulations generated over the last few days lie deposited on north-facing slopes atop expansively metamorphosed (faceted) old snow and are prone to triggering in some places. The snowpack surface is coloured brown from the deposited Sahara dust over widespread areas. Thereby, a smaller degree of solar radiation is reflected, which leads to a heightened degree of warmth in the snowpack. Due to this warming over the last two days, numerous superficial avalanches were released naturally. In the regions of the north where snowfall has been heaviest, increasingly frequent gliding avalanches have been observed. More deeply embedded inside the snowpack in the southern Valais and in the inneralpine and southern regions of Grisons more than anywhere else, there are pronounced weak layer evident. However, since the end of February, no fractures of dry-snow avalanches have been recorded as triggering in these layers. As a consequence of the beginning moistening-of-the-snowpack, fractures in these weak layers will once again become possible.

During the night of partly overcast skies, the snowpack was able to cool only to a small degree on the northern flank of the Alps. During the daytime the solar radiation was significantly reduced due to high-altitude cloud cover and Sahara dust. Most of the sunshine was registered in the eastern and the southern regions. Fresh snow: - Temperature: At midday at 2000 m, between a mild +8 °C in the western regions and +5 °C in the eastern regions. Wind: - Winds during the night on the northern Alpine Ridge and in the Jura region were blowing at moderate to strong velocity from southwesterly directions; - in the other regions of Switzerland, winds were light to moderate, blowing from westerly directions. Following a night of partly clear skies, it will be quite sunny during the daytime hours, in spite of high-altitude cloudbanks, but light conditions will be diffuse as a consequence of Sahara dust. The zero-degree level will be at approximately 3000 m, exceedingly mild. Fresh snow: - Temperature: At midday at 2000 m, between +5 °C in the northern regions and +2 °C in the southern regions. Wind: Winds will be blowing predominantly at light strength from easterly directions.

Friday: Nocturnal skies will be relatively overcast and the outgoing longwave radiation will be reduced. However, for the most part it will remain dry. During the daytime hours it will be partly sunny, in the Ticino skies will remain overcast for longer. At high altitudes a light to moderate easterly wind will be blowing, in the Prealps and in the Jura region there will be bise wind. Temperatures are expected to drop slightly. In the early morning hours the avalanche danger situation is quite favourable. During the course of the day, the danger of wet-snow and gliding avalnches increases swiftly. Saturday: Nighttime skies in the southern regions will be overcast, accompanied by a few snowflakes above approximately 1500 m. In all the remaining regions of Switzerland, skies will be predominantly clear. Saturday will be generally sunny. The zero-degree level in the northern regions will descend to approximately 2200 m, in the southern regions down to lower still. In the early morning hours, favourable conditions will prevail over widespread areas. As the daytime unfolds, the danger of wet-snow and gliding avalanches will increase.