Schreckhorn

The fresh snow and the wind slabs that are forming adjacent to ridgelines can be released by a single winter sport participant at elevated altitudes. In many cases the avalanches are medium-sized. Ski touring calls for experience in the assessment of avalanche danger. The surface of the snowpack will cool hardly at all during the overcast night. Individual wet avalanches are possible. This applies especially on very steep north facing slopes between approximately 2000 and 2600 m.

Whereas at intermediate altitudes rainfall and at higher altitudes moist snowfall have been registered, in high alpine regions a variety of layers of fresh snow and freshly generated snowdrifts have been deposited over the last few days. These layers are the main danger for dry-snow avalanches. On south-facing slopes the old snowpack is thoroughly wet far up into the high alpine regions, on west-facing and east-facing slopes the snowpack is wet below approximately 3000 m, and on north-facing slopes below approximately 2600 m. In spite of the gloomy weather, the process of the snowpack becoming thoroughly wet is progressing apace at high altitudes on north-facing slopes, although somewhat slowly.

Following a night of overcast skies, there were short bright intervals in the western and the northern regions on Wednesday. Above 2000 to 2200 m there were some snow showers. Fresh snow: Between Tuesday afternoon and Wednesday afternoon, the following amounts of fresh snow were registered above approximately 2500 m:

• Temperature: At midday at 2000 m, between +1 °C in the western regions and +5 °C in the furthermost eastern regions. Wind: In the high alpine regions during the course of the day, moderate strength southerly winds from region to region, in the other regions of Switzerland winds will be light.

Friday: During the night of overcast skies, the snowpack surface will hardly be able to freeze below approximately 2400 m. In the eastern and the southern regions, a few centimetres of fresh snow is expected above approximately 2000 m. On Friday morning in the western regions it will be quite sunny, in the eastern and the southern regions skies will continue to be overcast. During the course of the day, convective cloud build-up will bring isolated showers. In the western regions and at high altitudes in general, a moderate-strength northeasterly wind will be blowing. The danger of dry-snow avalanches is expected to incrementally decrease. Particularly in the western regions, wet-snow avalanches can be expected to release during the course of the day. For that reason, backcountry tours and ascents to mountain refuges need to be terminated early in the day. Saturday: During the night, skies are expected to swiftly clear up from the west. On Saturday it will be quite sunny to start with. During the course of the day, convective cloud build-up is anticipated, followed by isolated showers. The danger of dry-snow avalanches is expected to diminish. The dangaer of wet-snow avalanches will increase during the course of the day. Backcountry tours and ascents to mountain refuges should be brought to an end early in plenty of time.