untere Leventina

Wet avalanches during the day

Wet avalanches during the day

Only a little snow is lying. Individual avalanche prone locations for dry avalanches are to be found in particular on extremely steep slopes. Apart from the danger of being buried, restraint should be exercised in particular in view of the danger of avalanches sweeping people along and giving rise to falls. On very steep slopes individual gliding avalanches and wet snow slides are possible as the day progresses. Caution is to be exercised in areas with glide cracks. 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.

The snowpack surface is brown-coloured over widespread areas as a result of Sahara dust. This reduces the amount of solar radiation which gets reflected, which in turn heightens the warmth which is drawn into the snowpack. In spite of reduced solar radiation the snowpack on south-facing slopes below approximately 2400 m, and on east-facing and west-facing slopes below approximately 2100 m, is thoroughly wet. Particularly in the regions of the north where snowfall has been heaviest, numerous glide cracks have opened. Snowdrift accumulations which have been generated over the last few days were deposited on north-facing slopes atop expansively metamorphosed (faceted) old snow but are still prone to triggering only in isolated cases. More deeply embedded inside the snowpack, particularly in the southern Valais and in the inneralpine and southern regions of Grisons, there are pronounced weak layers 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 increased moistening of the snowpack, fractures in these weak layers have become possible once again.

Following a night of partly cloudy skies with reduced longwave outgoing radiation, it was very hazy during the daytime hours due to high-altitude cloudbanks and a great deal of Sahara dust in the atmosphere. Fresh snow: - Temperature: At midday at 2000 m, between +5 °C in the northern regions and +1 °C in the southern regions. Wind: Winds were blowing predominantly at light strength from easterly directions. Nighttime skies will be predominantly overcast and the outgoing longwave radiation significantly reduced. Above approximately 2200 m a small bit of snowfall is possible. In the northern regions the cloudiness will recede somewhat from the west during the daytime hours, but it will still remain hazy as a result of the Sahara dust. In the southern regions skies will remain overcast, but dry for the most part. Fresh snow: - Temperature: At midday at 2000 m, between +4 °C in the western regions and +1 °C in the southern and the eastern regions. Wind: - In the Jura region and the Prealps, a bise wind will be blowing at moderate to strong velocity; - in the other regions of Switzerland, a light to moderate strength easterly wind will be blowing.

Saturday: In the northern regions the bise wind will slacken off during the night and skies will gradually clear. During the daytime it will be quite sunny but significantly colder, with the zero-degree level at 2100 m. In the southern regions, nocturnal skies will be heavily overcast accompanied by a small amount of snowfall above approximately 1500 m, and during the daytime it will be partly cloudy. In the early morning the avalanche situation is quite favourable. Because the snowpack has little chance to cool during the night, the danger of wet-snow and gliding avalanches swiftly increases already during the morning. Sunday: In the northern regions, skies will be partly clear; the daytime will be rather sunny. In the southern regions skies will be overcast and a small amount of snowfall is possible above 1200 m by morning. In early morning the avalanche situation is favourable over widespread areas. During the daytime the danger of wet-snow and gliding avalanches increases somewhat in the northern and the inneralpine regions.