A lot of new snow. Considerable avalanche danger will be encountered over a wide area
Edition: 16.3.2021, 17:00 / Next update: 17.3.2021, 18:00
Snowpack
At elevated altitudes, large quantities of the abundant fresh snow has been transported and deposited very irregularly. Only the old snow cover remains on some ridges and peaks. In some instances, very large amounts of drifted snow is lying in bowls. The fresh snow is settling, but only slowly because of the low temperatures. The bonding between the fresh snow and the old snowpack is unfavourable on little used north facing slopes in particular, otherwise it is already quite good in some instances. Fractures within the fresh snow and wind slab layers remain likely.
Isolated avalanches capable of reaching the valley bottom were observed on Tuesday, some of which were also registered by the automatic detection systems.
Weak layers in the old snow near the ground persist in all aspects in particular in Valais and Grisons above approximately 2200 to 2400 m. Avalanche releases in these deep weak layers cannot be entirely ruled out where the fresh snow and snow drift accumulations of recent days give rise to excessive loading.
Observed weather on Tuesday, 16.03.2021
The north was mostly very cloudy. The primary focus of the snowfall shifted slowly eastwards. In Valais in particular there were bright spells during the day; Ticino was quite sunny.
Fresh snow
In the north on Tuesday, a further 20 to 50 cm of snow fell. From Saturday evening until Tuesday afternoon, therefore, the following aggregate amounts of snow fell above approximately 1600 m:
  • Lower Valais, regions north of a line between the Rhone and Rhine: 80 to 120 cm, but up to 170 cm in the far west and from the Urn Alps into the Glarus Alps
  • Mattertal, Lower Visp valleys, Goms, southern Gotthard region, rest of northern Grisons, northern Lower Engadine: 50 to 80 cm
  • Saastal, Simplon region, northern Ticino excluding Bedretto, central Grisons, southern Lower Engadine: 20 to 40 cm; further south, a few centimetres or none
Temperature
At midday at 2000 m: between -9 °C in the north and -6 °C in the south
Wind
  • Strong, occasionally storm force, veering from northwesterly to northerly
  • In Ticino, occasionally strong from the north
  • Easing during the day, in the west in particular
Weather forecast through Wednesday, 17.03.2021
The north will be mostly very cloudy and snow will fall, even at low altitudes. On the southern flank of the Alps it will be fairly sunny.
Fresh snow
From Tuesday afternoon until Wednesday afternoon above approximately 1200 m:
  • Jura, Lower Valais, regions north of a line between the Rhone and Rhine, Gotthard region, northern Grisons, northern Lower Engadine: 10 to 25 cm, but up to 40 cm from the eastern Bernese Oberland into the Glarus Alps
  • Southern Upper Valais, rest of northern Ticino, central Grisons, rest of Engadine: 5 to 10 cm; further south mostly dry
Temperature
At midday at 2000 m: between -8 °C in the north and -5 °C in the south
Wind
Moderate to strong from northerly directions
Outlook through Friday, 19.03.2021
Thursday
During the night the precipitation will cease in the northeast as well. During the day it will be mostly dry at first and, in the west and south in particular, partly sunny. In the afternoon dense cloud will build up again from the west. It will remain cold. The wind will be moderate at times from the north. The avalanche danger will decrease slowly. Solar radiation is expected to give rise to moist loose snow avalanches and gliding avalanches.
Friday
There will be variable to dense cloud cover, and a little snow will fall over a wide area. The avalanche danger will decrease slowly.