At elevated altitudes a considerable avalanche danger will be encountered in some regions
Edition: 14.5.2021, 17:00 / Next update: 15.5.2021, 18:00
Snowpack
The fresh snow and freshly generated snowdrift accumulations of this week are still prone to triggering in the high alpine regions more than anywhere else. During the course of the day, increasingly strong westerly to southwesterly winds will generate fresh snowdrift accumulations. In high alpine regions the conditions are rather wintery for this juncture of the season.
Below 2500 m the snow cover has become weakened by intensive rainfall, and north-facing slopes below 2500 m have become thoroughly wet.
As a consequence of reduced nocturnal outgoing longwave radiation on Friday night, only a very thin crust will be able to form on the snowpack surface. Beneath that crust the snowpack at intermediate and high altitudes is moist. Wet-snow and gliding avalanches continue to be possible in isolated cases.

The Avalanche Warning Service has only a small amount of information available from the outlying regions. For that reason, avalanche risks need to be examined with particular care on-site.
Observed weather on Friday, 14.05.2021
Skies on Thursday night were partially clear. During the morning hours on Friday it was quite sunny. During the afternoon, convective cloud build-up was registered, and there were showers reported from place to place. The snowfall level lay at 1600 m in the northern regions and at 2000 m in the southern regions.
Fresh snow
Only a few centimetres from place to place.
Temperature
At midday at 2000 m, 0 °C in the northern regions and +4 °C in the southern regions.
Wind
On Thursday night, winds will be blowing at light to moderate strength from westerly to northwesterly directions; winds will be light during the daytime on Friday.
Weather forecast through Saturday, 15.05.2021
On Friday night in the northern and the eastern regions, skies will be overcast to start with and a small amount of precipitation is anticipated from place to place. In the other regions of Switzerland the nighttime skies will be clear. During the morning hours on Saturday in western regions, skies will be predominantly overcast; in the southern and eastern regions it will still be sunny to begin with. Starting at midday, skies will become increasingly overcast and light precipitation is expected to set in from the west. In Grisons, it will presumably remain dry until afternoon. The snowfall level will lie at 1800 m.
Fresh snow
Between Friday afternoon and Saturday afternoon, the following amounts of fresh snow are anticipated above approximately 2200 m:
  • northern flank of the Alps, Valais, Ticino: 5 to 10 cm; on the northern Alpine Ridge and in the furthermost western part of Lower Valais: up to 15 cm from place to place.
Temperature
At midday at 2000 m, between 0 °C in the northern regions and +3 °C in the southern regions.
Wind
Winds will be westerly to southwesterly,
  • blowing at light to moderate strength from westerly to southwesterly directions during Friday night;
  • intensifying during the course of the day on Saturday, blowing at moderate to strong velocity in the northern and the western regions.
Outlook through Monday, 17.05.2021
Sunday
Skies are expected to be variably cloudy, accompanied by sunny intervals and showers (including thunderstorms) which could be quite intense in the northern and the western regions. The snowfall level will lie at 2000 m. A moderate-strength wind from westerly directions, in high alpine regions intermittently blowing at strong velocity, will prevail. Avalanche danger levels could increase to a certain extent from region to region.
Monday
Skies will be variably cloudy, accompanied by sunny intervals in the southern regions in particular, and in the western and northern regions more than anywhere else, thunderstorm-like showers. The snowfall level is expected to descend down to 1400 to 1600 m. At elevanted altitudes, a strong westerly wind will be blowing in some places. Avalanche danger levels are not expected to change significantly.