Persistent weak layers
- Above 2,200 m
Snowpack
In the regions south of a line from the Rhône to the Rhine, the persistent weak layers that have been a feature since the beginning of January are still present. The number of places where avalanches can be triggered by human activity in the weak layers of the old snowpack are continuing to decrease. However, any avalanches may still become large.
In the regions north of a line from the Rhône to the Rhine and in the extreme west of Lower Valais, weak layers in the snowpack are mostly thickly covered. Triggering by human activity is unlikely.
As a consequence of the falling temperatures, the continued moistening of the snowpack and deeper weak layers is slowing down. Gliding avalanche activity is continuing to decrease. Gliding avalanches can however become large, especially in the snowier west.
Weather forecast to Wednesday
Tuesday night into Wednesday will be partly cloudy with bright spells. There will be a little precipitation on the northern and southern flanks of the Alps, falling as snow above approximately 1600 m. During the day, it will be mostly sunny in the inneralpine regions of Valais and Grisons. On the northern flank of the Alps it will be partly sunny, whereas on the southern flank of the Alps, it will be very cloudy.
Fresh snow
Along the Prealps and on the southern flank of the Alps: a few centimetres above approximately 1600 m
Temperature
At midday at 2000 m, between +1 °C in the north and -1 °C in the south
Wind
From the southwest: initially mostly light, becoming increasingly moderate to strong in the Jura and along the Prealps as the day progresses
Weather review for Tuesday
Monday night into Tuesday was partly cloudy in the north and very cloudy in the south with little precipitation. During the day, it was mostly very cloudy on the western part of the northern flank of the Alps, in Valais and on the southern flank of the Alps, while elsewhere it was mostly sunny.
Fresh snow
A few centimetres above 1500 m on the Main Alpine Ridge between Zermatt and the Bernina Pass
Temperature
At midday at 2000 m, between +3 °C in the north and -1 °C in the south
Wind
From the south: generally light, but increasing to moderate in the regions exposed to the foehn wind in the north as the day progresses
Outlook to Friday
Overnight to Thursday, it will be mostly cloudy and there will be widespread light snowfall above approximately 1400 m in the north. During the day, it will gradually clear up in the west and south, but it will only be partly sunny on the central and eastern parts of the northern flank of the Alps and in northern Grisons. The wind will be mostly light and shift from a southerly to a northerly. Thursday night into Friday will be mostly clear. During the day it will be mostly sunny in the north and partly sunny in the south. The southwesterly wind will pick up as the day progresses. It will be appreciably milder in the north.
The danger of dry avalanches will increase slightly on Thursday, especially on the northern flank of the Alps. Elsewhere, it will not change significantly. The danger of wet and gliding avalanches will increase a little during the course of the day, especially in the north on Friday. Touring and off-piste descents should be completed in good time.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)