Zervreila

This week's fresh and drifted snow is gradually settling and consolidating. In the upper part of the old snowpack, there are some faceted weak layers and some snow-covered surface hoar, particularly on wind-protected shady slopes. On Saturday in particular, avalanches were triggered in these weak layers by winter sports participants. In the inneralpine regions of Valais and especially Grisons, the snowpack structure remains weak, and there is a possibility of isolated avalanches starting even in near-ground weak layers.

With light snowfall and northerly winds, mostly small snowdrift accumulations formed on Sunday, especially on the northern flank of the Alps. These will continue to grow during the course of Monday in all regions.

During the night, snow fell in the north down to low altitudes, mainly in the Prealps. During the day, it was mostly cloudy in the north. A few centimetres of snow fell locally. There were bright spells in Valais. In the south, conditions were very sunny.

Fresh snow

• Northern flank of the Alps: 10 to 15 cm, in the Prealps 15 to 25 cm
• less elsewhere; dry in the south

Temperature

At midday at 2000 m, around -7 °C in the north and -4 °C in the south

Wind

• Moderate to strong from north to northeast
• Moderate Bise wind in the western Prealps, sometimes strong in the Jura
• Moderate to strong foehn wind in the south

It will be cloudy in the north. Light snowfall will set in on Monday morning and intensify during the course of the day. The snowfall level will be between 600 and 900 m. In the south, it will be mostly sunny after a partly clear night.

Fresh snow

• Northern flank of the Alps, Lower Valais, northern and central Grisons: 5 to 10 cm; 15 cm from the eastern Bernese Alps to the Glarus Alps
• less elsewhere; dry in the south

Temperature

At midday at 2000 m, between -6 °C in the north and -3 °C in the south

Wind

• During the night into Monday, moderate northerly winds at high altitudes
• From the northwest and increasingly strong during the day, sometimes stormy in the afternoon
• Moderate to strong foehn wind in the south

In the north, it will be mostly very cloudy on both days and snow will fall down to low altitudes. In the south, it will be mostly sunny on both days. In Valais, it will be partly sunny on Tuesday and quite sunny on Wednesday. From Monday afternoon to Wednesday afternoon, 50 to 80 cm of snow will fall on the northern flank of the Alps from the eastern Bernese Alps to the Glarus Alps and in Grisons north of the Anterior Rhine. 30 to 50 cm will fall on the rest of the eastern part of the northern flank of the Alps and in the rest of northern and central Grisons. There will be 10 to 30 cm of snow elsewhere. It will remain largely dry south of the Main Alpine Ridge. At high altitudes, the wind will be strong to stormy from northerly directions and will transport the fresh snow as well as loose old snow. In the south, there will be a sometimes strong foehn wind. Over the course of Wednesday, the wind will ease at high altitudes and a strong Bise wind will rise in the Jura.

In the north, the avalanche danger will increase significantly during the night into Tuesday across a wide area. On Tuesday, the avalanche danger is expected to reach danger level 4 (high) in the regions exposed to heavier precipitation on the northern flank of the Alps and in northern Grisons, with naturally triggered avalanches to be increasingly expected. These may be very large on the northern flank of the Alps and exposed parts of transportation routes may be in danger. In northern Grisons, the danger will primarily affect alpine snow sports terrain. Naturally triggered avalanche activity will decrease during the course of Wednesday. However, the situation will remain very critical for snow sports outside marked and open pistes.

The avalanche danger will increase somewhat in places in the south on Tuesday, and will not change significantly on Wednesday.