Saint-Cergue

Considerable avalanche danger will be encountered over a wide area

Considerable avalanche danger will be encountered over a wide area

As a consequence of new snow and a strong southwesterly wind, wind slabs will form in the course of the day. The fresh wind slabs are mostly small but can be released in isolated cases. Individual avalanche prone locations are to be found in particular in gullies and bowls, and behind abrupt changes in the terrain. Apart from the danger of being buried, restraint should be exercised in particular in view of the danger of avalanches sweeping people along and giving rise to falls.

As a consequence of strong-velocity southwesterly and foehn winds, generally medium-sized snowdrift accumulations are being generated. These accumulations are frequently being deposited atop a loosely-packed old snowpack surface and are prone to triggering. Furthermore, there are weak layers evident more deeply embedded inside the snowpack. These layers are generally well covered in the central and eastern sectors of the northern flank of the Alps and are hardly prone to triggering. In the western sector of the northern flank of the Alps they are prone to triggering from place to place. From the southern Valais over the northern Ticino as far as Grisons, the weak layers inside the old snowpack are particularly pronounced. There, particularly on less-frequented, very steep shady slopes, avalanches can be triggered by persons in the weakened old snowpack. In places where the snow is shallow and in transition zones from shallow to deep snow, the avalanche prone locations occur most frequently.

Following a night of clear skies it was sunny. Fresh snow: - Temperature: At midday at 2000 m, between 0 °C in the northern regions and -6 °C in the southern regions. Wind: - Winds were blowing predominantly at light strength, intermittently at moderate strength, from southwesterly directions; - in the foehn-impacted valleys mostly at moderate strength, intermittently strong-velocity southerly foehn wind. During the night, cloud cover will move in from the west also into southern regions. During the daytime tomorrow, light snowfall is expected to set in from west and south. The snowfall level in the western regions will lie initially at 1400 m, subsequently descend by evening down to low lying areas. In the southern regions the snowfall level will lie at approximately 500 m. Further east, as a result of foehn winds in the morning hours, it will be quite sunny and it will remain dry until evening. Fresh snow: By Monday afternoon: - summit zones of the western Jura region: 10-20 cm; - remaining parts of the Jura region, furthermost western part of the Lower Valais, Valais sector of Main Alpine Ridge, Val Moesa, Bergell, Bernina region, Val Poschiavo: only a few centimetres; - in the remaining regions of Switzerland, generally dry. Temperature: At midday at 2000 m, -2 °C in the northern regions and -6 °C in the southern regions. Wind: - Winds in the foehn-impacted valleys of the north, strong-velocity foehn wind, further east persisting during the course of the day; - in the Jura region, along the Prealps and in general at high altitudes, strong-velocitdy southwesterly wind.

Tuesday: On Monday night, snowfall down to low lying areas is anticipated over widespread areas. During the daytime on Tuesday, snowfall will persist in the northern regions. In the southern regions the snowfall will terminate and it will become increasingly sunny. In the Engadine skies will remain overcast for somewhat longer. At high altitudes a moderate-to-strong velocitdy northwesterly wind will be blowing. Avalanche danger levels will increase over widespread areas as a result of fresh fallen snow and winds. In the western part of the Jura region, in the furthermost western part of the Lower Valais and in the southern regions of Grisons, these conditions will prevail already on Monday night; in the remaining regions of Switzerland, they will arrive during the course of the day on Tuesday. Wednesday: In the northern regions, intermittent precipitation is anticipated. The snowfall level is expected to ascend to 2000 m in the western regions during the course of the day, in the eastern regions to 1600 m. In the southern regions it will be partly sunny and somewhat less mild. At high altitudes and in the northern regions, a strong-velocity westerly to southwesterly wind will be blowing. The danger of dry-snow avalanches is not expected to change significantly at high altitudes. As a result of rainfall below approximately 2000 m in the western and the northern regions, naturally triggered dry-snow and moist-snow avalanches can be expected.