Pays d'Enhaut

Weakly bonded old snow and gliding snow require caution

Weakly bonded old snow and gliding snow require caution

Gliding snow represents the main danger. In starting zones where no previous releases have taken place more medium-sized and, in isolated cases, large gliding avalanches are possible. This applies on sunny slopes below approximately 2400 m, and on shady slopes below approximately 2000 m. Gliding avalanches can be released at any time of day or night. Areas with glide cracks are to be avoided. Individual avalanche prone locations for dry avalanches are to be found in particular on shady slopes above approximately 2200 m. Avalanches can in isolated cases be released by people, especially at transitions from a shallow to a deep snowpack. At elevated altitudes mostly small wind slabs formed. Meticulous route selection is recommended.

In the lower part of the snowpack, particularly on west-facing, north-facing and east-facing slopes above approximately 2200 m, weak layers are evident. In the western part of Lower Valais and on the northern flank of the Alps these ground-level layers have been covered over with thick layers of fresher snow, which makes the possibility of them being triggered by persons far smaller. From central Valais over the Ticino as far as Grisons, as well as generally in places where the snow is shallow, the snowpack layering is least favourable. In those places, avalanches can still be triggered in the old snow by persons. The activity of gliding avalanches is currently high. Also in the next few days, additional gliding avalanches can be expected on steep grass-covered slopes which have not yet discharged. These releases can occur at any time of day or night. In the regions of the west and the north where recent snowfall has been heaviest, these releases can grow to large size in some places. As a result of daytime warming and solar radiation, the snowpack on steep south-facing slopes will become superficially moist. During a night of clear skies on Thursday, a melt-freeze crust will form on the snowpack surface. On steep south-facing slopes this crust will be capable of bearing loads in the morning.

On Thursday it was sunny in the mountains, following a night of clear skies. Fresh snow: - Temperature: - At midday at 2000 m, +9 °C in the southern regions, +7 °C in the western regions and +4 °C in the eastern regions; - the zero-degree level in the western regions lay at over 3000 m, in the eastern regions at 2500 to 2800 m. Wind: - Winds at high altitudes were blowing at moderate to strong velocity from northeasterly directions; - in the Ticino, a moderate strength northerly foehn wind prevailed. Following a night of clear skies it is expected to be sunny in the mountains. Fresh snow: - Temperature: - At midday at 2000 m, +7 °C in the southern regions, +5 °C in the western regions, and +3 °C in the eastern regions; - the zero-degree level during the morning will lie at 3000 m over widespread areas; descending somewhat during the afternoon in the eastern regions. Wind: - Winds will be blowing at light to moderate strength from northerly to easterly directions; - during the course of the day, northerly foehn wind will be blowing once again on the southern flank of the Alps.

In the mountains it will be sunny and mild on both days. Winds will be blowing predominantly at light to moderate strength from northerly to easterly directions. The danger of dry-snow avalanches will continue to decrease incrementally. Particularly in the inneralpine regions as a result of the persistent weak layer, avalanche triggerings caused by persons continue to be possible. The danger of gliding avalanches will remain upright.