Considerable avalanche danger will be encountered over a wide area
Edition: 13.3.2021, 17:00 / Next update: 14.3.2021, 18:00
Snowpack
As a result of fresh fallen snow and strong-velocity winds, large-sized snowdrift accumulations are being generated in the northern regions and in the Valais. In the remaining regions of Switzerland the snowdrift accumulations are not as deep. Fresh snow and freshly-generated snowdrifts are prone to triggering. In isolated cases, avalanches can also sweep along more deeply embedded parts of the old snowpack, particularly on shady slopes above approximately 2200 m.
Weak layers in the ground-level segment of the old snowpack are ongoingly evident in the Valais and in Grisons above approximately 2200 to 2400 m in all aspects. Avalanches fracturing in these more deeply embedded weak layers are unlikely in the immediate future.
Observed weather on Saturday, 13.03.2021
Following a night of predominantly clear skies, it was quite sunny. During the afternoon, cloudbanks moved in from the west.
Fresh snow
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Temperature
At midday at 2000 m, between -2 °C in the northern regions and 0 °C in the Valais and in the Ticino.
Wind
Winds in the western regions were frequently blowing at strong velocity, otherwise blowing predominantly at moderate to strong velocity, from southwesterly directions.
Weather forecast through Sunday, 14.03.2021
During the nocturnal hours tonight, snowfall over widespread areas is anticipated. During the daytime in the furthermost southern regions it will be quite sunny, in the other regions of Switzerland frequent snowfall is expected. The snowfall level will lie at 600 m.
Fresh snow
Between Saturday afternoon and Sunday afternoon, the following amounts of snowfall are anticipated above approximately 1500 m:
  • from the Trient region as far as the Great St. Bernard: 40 to 60 cm;
  • western part of Jura region north of an imaginary Rhine-Rhone line, Lower Valais, Prättigau, northern Lower Engadine: 20 to 40 cm;
  • eastern part of Jura region, southern Upper Valais, remaining parts of Gotthard region, central Grisons, southern Lower Engadine, Upper Engadine north of the Inn: 10 to 20 cm;
  • further towards the south: less than 10 cm; in the Sotto Ceneri it will remain predominantly dry.
Temperature
At midday at 2000 m, -8 °C.
Wind
Winds will be blowing at strong to storm-strength, during the nighttime hours from westerly directions, during the daytime from northwesterly directions.
Outlook through Tuesday, 16.03.2021
On Monday and on Tuesday in the northern regions, persistent snowfall down to low lying areas is anticipated. On Tuesday the snowfall is expected to slacken off in western regions during the course of the day. Only in the furthermost southern regions will it be intermittently sunny on both days. A strong-to-storm strength northwesterly wind will be blowing.
Avalanche danger levels are expected to continue to increase on Monday. On the northern Alpine Ridge, in the Lower Valais, in northern Grisons and in the Lower Engadine north of the Inn, Danger Level 4 (high) will presumably be reached over widespread areas. Increasingly frequent naturally triggered avalanches can be expected, including very large-sized releases. Exposed sectors of transportation routes will be placed at risk. On Tuesday the avalanche situation will remain critical. In the remaining regions of Switzerland, Danger Level 4 will hardly be reached. In the furthermost southern regions the avalanche situateion will remain predominantly favourable.