Wind slab
- Above 2,600 m
Snowpack
In the high alpine regions, the larger amounts of new snow from the last four days and the drifted snow are still prone to triggering in some cases. In addition, weak layers are embedded in the near-surface layers of the old snowpack, especially on steep north-facing slopes. Avalanche observations from recent days confirm that these weak layers are prone to triggering.
A crust has formed beneath the new snow. Below this, the old snowpack is moist up to high altitudes. As a consequence of solar radiation, loose snow avalanches are to be expected on very steep slopes, especially in the regions with a lot of fresh snow. Wet snow avalanches, which can sweep away the entire snowpack, are possible in isolated cases, especially as the day progresses. This applies particularly to north-facing slopes between 2200 and 2600 m, where the snowpack is becoming saturated for the first time.
Weather forecast to Friday
Skies will mostly be clear overnight to Friday. During the day, it will be quite sunny with cumulus clouds and isolated showers and thunderstorms as the day progresses.
Fresh snow
-
Temperature
At midday at 2000 m, around +6 °C
Wind
Mostly light from southerly directions, moderate at times in the high alpine regions
Weather review for Thursday
During the night into Thursday, precipitation continued to fall, mainly in Ticino and Grisons. During the day, there were sunny spells between residual cloud and cumulus clouds. Valais, Ticino and southern Grisons saw the most sun.
Fresh snow
From Wednesday afternoon to Thursday afternoon with a snowfall level of 1700 to 2000 m:
This means that over the four days from Sunday afternoon to Thursday afternoon, altitudes above approximately 2800 m saw the following snowfall:
Temperature
At midday at 2000 m, between +2 °C in the northeast and +7 °C from the Visp valleys to western Ticino
Wind
Southwesterly
Outlook to Sunday
The night into Saturday will be mostly clear. During the day, it will be quite sunny on the southern flank of the Alps, otherwise mostly sunny with cumulus clouds and isolated showers as the day progresses. During the night into Sunday, cloud cover will increase from the southwest. On the southern flank of the Alps, it will be very cloudy with showers as early as the late morning. On the central and eastern parts of the northern flank of the Alps and in northern Grisons, there will be a foehn wind and it will still be partly sunny at first. Cloud cover will increase here as well later on. The zero-degree level will be around 3000 m on both days.
The danger of dry avalanches will decrease. Caution is still required in particular on steep north- and east-facing slopes in regions with a lot of fresh snow at high altitudes. On Saturday, the danger of wet avalanches will change in the course of the day; on Sunday, it will increase even in the early morning, especially on the southern flank of the Alps. Otherwise it will increase as the day progresses. Isolated wet avalanches which sweep away the entire snowpack are possible, especially on north-facing slopes between 2200 and 2600 m.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)