südliches Urseren

Considerable avalanche danger will be encountered over a wide area

Considerable avalanche danger will be encountered over a wide area

The new snow and wind slabs of the last few days are lying on top of a weakly bonded old snowpack. Even single winter sport participants can release avalanches easily. Avalanches can be triggered in the old snowpack and reach large size. Remotely triggered avalanches are possible. Whumpfing sounds and the formation of shooting cracks when stepping on the snowpack serve as an alarm indicating the danger. Backcountry touring and other off-piste activities call for extensive experience and restraint.

The frequently deep layers of fresh fallen snow and freshly generated snowdrift accumulations from Tuesday and Wednesday lie deposited atop a pronounced weak layer on west-facing, north-facing and east-facing slopes. From the southern Valais over the northern Ticino as far as Grisons, furthermore, the entire old snowpack is expansively metamorphosed in numerous places. Avalanche triggerings by persons are still easily possible in all regions with the exception of the southern flank of the Alps. This applies in particular to the inneralpine regions. The likelihood of avalanches triggering is decreasing only gradually on west-facing, north-facing and east-facing slopes. As a consequence of westerly winds, predominantly small-sized snowdrift accumulations were generated in the western and the northern regions on Friday. As a result of the fresh snow, these are expected to expand somewhat further on Saturday. At intermediate altitudes, gliding avalanches continue to be possible in isolated cases.

Following a night of predominantly clear skies, it was sunny in the mountains during the daytime. In the afternoon, cloud cover moved in from the northwest. Fresh snow: - Temperature: At midday at 2000 m, 0 °C. Wind: Winds in the Jura region and on the northern flank of the Alps were blowing at moderate to strong velocity during the nocturnal hours, during the daytime blowing at moderate strength, in the other regions blowing at light to moderate strength, from westerly directions. On Friday night in the northern regions a small amount of snowfall is anticipated. The snowfall level will descend from 1200 m down to approximately 800 m. In the northern and the eastern regions it will become increasingly sunny after residual clouds disperse. In the Valais and the southern regions it will be predominantly sunny. Fresh snow: Between Friday evening and Saturday morning the following amounts of fresh snow are expected above approximately 1200 m: - northern flank of the Alps from the eastern Bernese Alps as far as Liechtenstein: 5 to 10 cm, up to 15 cm from place to place; - in the other regions of Switzerland only a few centimetres; in the southern regions it will remain dry. Temperature: At midday at 2000 m, -6 °C in the northern regions and -2 °C in the southern regions. Wind: Winds during the nighttime hours of Friday will be predominantly moderate, during the daytime on Saturday light to moderate, from westerly to northwesterly directions.

Sunday: It will be quite sunny to begin with in the northern regions, accompanied by cloudbanks. During the course of the day, heavy cloud cover will move in from the northwest, but it is expected to remain dry by and large until afternoon. In the southern regions it will be predominantly sunny. The westerly winds will intensify at high altitudes, be blowing at strong velocity, and at storm-strength during the afternoon. Avalanche danger levels will increase somewhat during the course of the day as a result of the freshly generated snowdrift accumulations. Monday: Skies will be heavily overcast and snowfall is anticipated over widespread areas, falling down to low lying areas, presumably bringing 30 to 50 cm of fresh snow in the northern regions. Only in the furthermost southern regions will it remain dry and partly sunny. Winds will be blowing at strong to storm strength from westerly to northwesterly directions. The avalanche danger levels are expected to increase over widespread areas.