Waadtländer Voralpen

At elevated altitudes a considerable avalanche danger will be encountered over a wide area.

The fresh and older wind slabs are in some cases still prone to triggering. The avalanche prone locations are to be found in particular in gullies and bowls, and behind abrupt changes in the terrain and adjacent to ridgelines. Avalanches can reach medium size. The wind slabs are to be evaluated with care and prudence in particular in steep terrain.

As the day progresses small to medium-sized gliding avalanches and moist snow slides are possible.

Snowpack Last week’s large quantities of fresh snow and snow drift accumulations are becoming more and more stable but remain prone to triggering in some cases. In addition, faceted and weak layers exist in some instances near the surface of the old snowpack in the vicinity of melt-freeze crusts. On west, north and east facing slopes, weak layers also exist near the base of the snowpack. In particular in the inneralpine regions of both Valais and Grisons, these layers remain prone to triggering, especially in areas with shallow snow cover. Solar radiation and warming during the day made the snow surface moist. During Monday night, when the skies will be clear only at times, a brittle melt-freeze crust will form. It will soften quickly during the day. Observed weather review Monday, 17.04.2023 In the period to Monday morning, a further 10 to 15 cm of snow fell in the central and eastern parts of the northern flank of the Alps. The snowfall level was approximately 1400 m. During the day it was fairly sunny, but convective cloud built up in the afternoon. In the Prealps and the Jura it was mostly cloudy. Fresh snow From the onset of the precipitation on Friday evening until Monday morning, the following amounts of snow fell above approximately 2000 m:

• Northern Alpine ridge 30 to 50 cm, from the Grimsel Pass into the Glarus Alps up to 80 cm
• Rest of the northern flank of the Alps, Lower Valais, northern Grisons, Silvretta, Samnaun: 15 to 30 cm, but locally up to 40 cm
• Western Jura, rest of Valais, rest of Grisons: 5 to 15 cm
• Elsewhere: a few centimetres or none

Temperature At midday at 2000 m: between -2 °C in the north and +2 °C in the south Wind

• Mostly light, moderate at times from northeasterly directions
• In the Jura, a moderate to strong bise

Weather forecast through Tuesday, 18.04.2023 On Monday night the skies will be only partly clear. In southern Valais a little snow will fall above approximately 1800 m. During the day it will be quite sunny. As the day progresses, convective cloud will build up to an increasing extent and some scattered showers are possible, in particular in the north and west. Fresh snow In southern Valais: locally 5 to 10 cm Temperature At midday at 2000 m: between +1 °C in the north and +3 °C in the south Wind

• Generally light
• In the Jura on Monday night, a moderate to strong bise, easing during the day

Outlook through Thursday, 20.04.2023 Wednesday On Tuesday night the skies will be mostly clear. During the day it will be quite sunny with convective cloud. Some local showers or thunderstorms are possible. The zero degree level will be between 2500 m in the southwest and 2100 m in the northeast. The wind will be light, but moderate to strong at times in the central part of the main Alpine ridge, from the north. The danger of dry avalanches will decrease. The danger of wet snow avalanches will increase during the day. Thursday On Thursday there will be variable to dense cloud cover and precipitation will fall at times, in particular in the south. The snowfall level will be between 1000 m in the north and 1600 m in the south. Above 2000 m in the central and eastern parts of the northern Alpine ridge, 15 to 30 cm of snow could fall. The wind will be moderate to strong from the southwest to west. The danger of dry avalanches will increase in the regions exposed to heavier precipitation. The danger of wet snow avalanches will decrease.