Haut Val de Bagnes

Weakly bonded old snow in the inneralpine regions

Weakly bonded old snow in the inneralpine regions

Distinct weak layers deep in the old snowpack necessitate caution, especially on very steep shady slopes, as well as on south facing slopes above approximately 2800 m. Here avalanches can be triggered in the weakly bonded old snow and reach a dangerous size. These avalanche prone locations are to be found especially in little used terrain and at transitions from a shallow to a deep snowpack. These places are barely recognisable, even to the trained eye. Whumpfing sounds can indicate the danger. Defensive route selection is required. Maintaining distances between individuals and one-at-a-time descents are recommended, especially on very steep shady slopes.

In the lower part of the snowpack, particularly on west-facing, north-facing and east-facing slopes above approximately 2200 m, there are weak layers evident. In western Lower Valais and on the northern flank of the Alps these ground-level layers are covered by thick layers of fresher snow so that the likelihood of avalanches being triggered by persons is low. From central Valais over the Ticino as far as Grisons the snowpack layering is least favourable. In those regions there have been isolated medium-sized avalanches triggered by persons during the last few days. The activity of gliding avalanches is continuing to diminish incrementally. Nevertheless, gliding avalanches continue to be possible on steep grass-covered slopes which have not yet discharged in isolated cases. During a night of clear skies on Sunday, a melt-freeze crust which is capable of bearing loads will form on the snowpack surface of very steep south-facing slopes. As a consequence of daytime warming and solar radiation, the snowpack surface will become moist on steep south-facing slopes.

Following a night of clear skies it was sunny in the mountains during the daytime. Fresh snow: - Temperature: At midday at 2000 m, between +5 °C in the western and the southern regions and +1 °C in the eastern regions. Wind: Winds in the central and eastern sectors of the Main Alpine Ridge were blowing at moderate to strong velocity from northerly directions; in the other regions winds were light to moderate. Following a night of clear skies it will be sunny in the mountains during the daytime. Fresh snow: - Temperature: At midday at 2000 m, between +2 °C in the western and the southern regions and -1 °C in the eastern regions. Wind: Winds in the high alpine regions will be blowing at moderate to strong velocity from northerly to northeasterly directions; in the other regions of Switzerland winds will be light to moderate.

On both days it will be sunny in the mountains. The danger of dry-snow avalanches is not expected to change significantly. Gliding avalanches continue to be possible in isolated cases.