High Alpine regions: Wind slabs are to be evaluated critically
Edition: 23.5.2021, 17:00 / Next update: 24.5.2021, 18:00
Snowpack
At heightened altitudes snow depths are above average for this juncture of the season. Particularly in the high alpine regions, conditions are wintery.
Fresh fallen snow and snowdrifts from the last few days are still prone to triggering in some places on north-facing and east-facing slopes in high alpine regions more than anywhere else.
As a consequence of daytime warming and the soon anticipated rainfall, small-to-medium wet-snow and gliding avalanches are possible below 2500 m in particular.
Observed weather on Sunday, 23.05.2021
Skies during the nocturnal hours were heavily overcast for the most part. Precipitation was registered over widespread areas. The snowfall level in the northern regions descended from 2000 m down to 1500 m; in the southern regions from 2200 m down to 1800 m. In the early morning hours, skies cleared up starting in the west. Subsequently it became sunny, including in the eastern regions during the afternoon. Convective cloud build-up was registered.
Fresh snow
Between Saturday afternoon and Sunday morning, the following amounts of fresh snow were registered above 2200 m:
  • Main Alpine Ridge from Rheinwaldhorn as far as Bernina Pass, Silvretta: 15 to 30 cm;
  • in the other regions of Switzerland, in Trient, the Urner Alps as well as the other parts of Grisons south of the Rhine, as much as 20 cm.
Temperature
At midday at 2000 m, in the northern regions at 0 °C and in the southern regions at +4 °C.
Wind
Winds were blowing at moderate strength from westerly to southwesterly directions.
Weather forecast through Monday, 24.05.2021
Nighttime skies on Sunday night will be predominantly overcast. In the northern regions, weather will be foehn-influenced. In the southern regions, precipitation is expected to set in, which subsequently will spread over the northern flank of the Alps during the course of the day. The snowfall level will lie between 1800 and 2200 m.
Fresh snow
The following amounts of fresh snow are anticipated above 2500 m by Monday afternoon:
  • Main Alpine Ridge from Monte Rosa as far as Bernina Pass and southwards therefrom: 10 to 25 cm;
  • in the other regions of Switzerland, generally less.
Temperature
At midday at 2000 m, at +2 °C.
Wind
Winds will be blowing at moderate to strong velocity from southerly to southwesterly directions.
Outlook through Wednesday, 26.05.2021
On Monday night the precipitation will come to an end, including in the northern regions. On Tuesday and on Wednesday, skies will be variably cloudy. Some precipitation is possible in the form of showers.
The danger of dry-snow avalanches demands attentiveness in the high alpine regions in particular. In addition, as a result of the daytime warming and solar radiation, wet-snow and gliding avalanches are possible.