Waadtländer Voralpen

As a consequence of new snow and wind a considerable avalanche danger will be encountered over a wide area

As a consequence of new snow and wind a considerable avalanche danger will be encountered over a wide area

As a consequence of new snow and a strong westerly wind, sometimes easily released wind slabs will form especially adjacent to ridgelines. Mostly avalanches are small. The wind slabs are to be avoided especially in very steep terrain. On very steep grassy slopes gliding avalanches and moist snow slides are possible.

Loosely-packed snow was transported in many places on Wednesday due to strong-velocity southwesterly to northwesterly winds. Snowdrift accumulations formed which are prone to triggering. On Thursday as a result of renewed snowfall plus moderate to strong-velocity winds, further snowdrift accumulations are expected to form on the northern flank of the Alps, in Lower Valais as well as in the Jura region more than anywhere else. Prior to the bouts of snowfall over the last five days there was very little snow on the ground in the western and the northern regions. In the Jura region and the Prealps, the snow fell predominantly on bare ground. Wherever there was snow previously, the bonding of the fresh snow and fresh drifts to the thin old snowpack beneath it is unfavourable, particularly on west-facing, north-facing and east-facing slopes above approximately 2000 m. Avalanches can be triggered in the transition zone between these layers. Below 2000 m, gliding avalanches continue to be expected on grass-covered slopes on the northern flank of the Alps more than anywhere else. These releases can grow to medium size.

On Tuesday evening snowfall was registered above 800 m in the northern regions. Subsequently the skies cleared up. In the southern regions skies were clear. During the morning hours, cloud cover swiftly moved in from the northwest. Subsequently in the Jura region, in the western sector of the northern flank of the Alps and in the Valais, precipitation set it. The snowfall level in the Jura region and on the northern flank of the Alps lay at approximately 1300 m, in the Valais it snowed down to low lying areas. In the eastern and southern regions skies were partly overcast in the afternoon, but it remained dry. Fresh snow: Between Tuesday midday and Wednesday midday the following amounts of fresh snow were registered above 1500 m: - northern Prättigau: 20 to 30 cm; - central and eastern sectors of the northern flank of the Alps, remaining regions of northern Grisons, as well as the Silvretta and the Samnaun: 10 to 20 cm; - in the other regions of Switzerland, less; or else it remained dry. Temperature: At midday at 2000 m, 0 °C in the northern regions and -2 °C in the southern regions. Wind: During the nocturnal hours winds were blowing intermittently at strong velocity from westerly to northwesterly directions, during the daytime blowing at moderate to strong velocity from the southwest. In the northern regions skies will be heavily overcast and snowfall is anticipated which will be persistent in the furthermost western part of the Valais and on the northern flank of the Alps. The snowfall level is expected to descend down to low lying areas during the night. In the southern regions and in the Engadine, a small amount of snowfall is possible during the night, but during the daytime hours it will be dry and partly sunny. Fresh snow: Between Wednesday midday and Thursday afternoon, the following amounts of fresh snow are anticipated above 1200 m: - northern flank of the Alps, furthermost western part of the Valais, western Jura region: 15 to 30 cm, as much as 40 cm along the Valais border to France and in the Vaud Alps; - remaining parts of the Lower Valais, Upper Valais, northern Grisons: 5 to 15 cm; - in the other regions of Switzerland, only a few centimetres. Temperature: It is expected to become increasingly cold. At midday at 2000 m, between -7 °C in the northern regions and -4 °C in the southern regions. Wind: Winds will be blowing at moderate to strong velocity from westerly to northwesterly directions.

On Thursday night the snowfall expected to come to an end in the northern regions. On Friday it will be partly sunny on the northern flank of the Alps. In the southern regions it will be sunny and dry as a result of strong-velocity northerly winds. On Friday night, precipitation will set in once again, from the west. On Saturday, persistent snowfall is expected in the northern and the western regions. The snowfall level will lie between 1000 and 1500 m. In the southern regions it will be dry and partly sunny. On Friday in the northern regions, avalanche danger levels are not expected to change, on Saturday the danger levels could increase somewhat. In the southern regions, avalanche danger will continue to decrease gradually.