22.01.2018 | 18:00 | News
Very high avalanche danger will be encountered over a wide area
Following a situation in which there were already extraordinary amounts of snow on the ground, an additional 80 to 100 cm of fresh snow have been registered since Saturday in the Valais, on the northern flank of the Alps and in northern Grisons, as much as 150 cm of new snow in the valleys of Visp and the Glarner Alps. Between Monday evening and the end of this period of precipitation sometime on Monday night, an additional 20 to 40 cm of fresh snow is still anticipated.
The SLF continues to rank the current avalanche danger in far reaching parts of the Valais and of the northern Alpine Ridge at the highest avalanche danger level (5, “very high”).
Until the end of this period of precipitation, many avalanches, some of them very large, can be expected. These avalanches can flow down to the valleys and place seldom endangered transportation routes and buildings at risk. Following the end of this precipitation event, the frequency of avalanches will diminish, but not their size.
The instructions issued by public offices and local safety authorities must be heeded. In the regions concerned, it is advised to refrain from any skiing and freeriding activities away from secured ski runs.
Just how unusual is this situation?
The danger level “very high” only prevails very rarely. The last time this rank was assigned over such wide-ranging surface areas was in February 1999, for an extended period.
Regarding the amount of snowfall, the current situation is extraordinary:
During the last six days, automatic weather stations (situated at 2000 to 2500 m elevation) have registered 200 to 300 cm of snowfall. These overall amounts of new snow are comparable with those in the third, most intense period of precipitation in February 1999. At isolated lower-elevation measurement stations with data extending back over many years the amount of new snow over the last six days corresponds to amounts which only occur every twenty years: Arosa (182 cm), Davos (159 cm) and Ulrichen (159 cm). At most of the other stations, the amounts of new snow that were measured today are registered approximately every five to ten years.
Climatological classification of snow depths and new snow 22 January 2018, 8:00 am
For details regarding the avalanche danger: https://www.slf.ch/en/avalanche-bulletin-and-snow-situation.html