Waadtländer Voralpen

Moderate avalanche danger will be encountered over a wide area. Wind slabs require caution

Moderate avalanche danger will be encountered over a wide area. Wind slabs require caution

In particular in gullies and bowls and behind abrupt changes in the terrain as well as at elevated altitudes wind slabs formed. These are mostly small but in some cases prone to triggering. They are easy to recognise and to be assessed with care and prudence. Apart from the danger of being buried, restraint should be exercised as well in view of the danger of avalanches sweeping people along and giving rise to falls.

Fresh fallen snow and newly generated snowdrifts from the last few days have been deposited to some extent on an unfavourable old snowpack surface and are prone to triggering. Beneath the fresh snow and fresh snowdrifts the snowpack layering in the Jura region, on the northern flank of the Alps and in the western part of the Lower Valais is predominantly favourable, except in the vicinity of rain crusts which formed at the end of December. In those zones there are weak layers evident which are prone to triggering from place to place. From the central part of the Valais over the northern part of Ticino as far as Grisons, the snowpack is frequently expansively metamorphosed (faceted) and riddled with thin melt-freeze crusts. In places where snow is shallow, you can break through down to the ground. As as result of the expansive metamorphosis, the tendency towards fracture propagation has receded and in the last few weeks there have hardly been any avalanche triggerings registered in the old snow. In the furthermost southern regions there is very little snow on the ground.

In the northern and the eastern regions, skies were heavily overcast for the most part and in the eastern regions there was a small amount of snowfall down to low lying areas during the course of the day. In the furthermost western regions, in the Valais, and south of the Main Alpine Ridge it was generally sunny. Fresh snow: - Temperature: Temperatures rose. At midday at 2000 m, between -4 °C in the western regions, -7 °C in the eastern regions, and -1 °C in the southern regions. Wind: - in the Jura region and in the western Prealps: moderate to strong-velocity bise wind; - in the southern regions: moderate to strong-velocity northerly foehn wind; - in the Alpine ridges, frequently strong-velocity, in the other regions of Switzerland mostly moderate winds from northeasterly directions. On Saturday night skies will be predominantly clear except in the furthermost eastern regions. There, during the early part of the night, there will be a few snowflakes falling before skies clear up. During the day on Sunday it will be predominantly sunny in the mountains. The upper border of the fog will lie at 1000 to 1400 m in the northern regions. Fresh snow: - Temperature: Temperatures are expected to rise. At midday at 2000 m, +2 °C in the western and the southern regions, and -2 °C in the eastern regions. Wind: - Winds in the Jura region and in the Prealps: light to moderate bise wind; - in the southern regions: on Saturday night, northerly foehn wind will slacken off; - at high altitudes in general: also slackening off, blowing predominantly at moderate strength, from northerly to northeasterly directions.

Following nights of clear skies it will be sunny in the mountains on both days. The northerly winds will be blowing at light to moderate strength. The zero-degree level will lie at 2400 m to 2600 m at midday in the western and the southern regions, at 1800 m to 2200 m in the eastern regions. The danger of dry-snow avalanches is expected to decrease, however only gradually on shady slopes. On steep sunny slopes, moist slides and gliding avalanches will be possible during the course of the day.