obere Maggiatäler

Snowpack

After some clear nights over the last few days, the surface of the snowpack is often angular and loose. This is unfavourable in view of the upcoming snowfall. With new fallen snow and increasing wind, fresh snowdrift accumulations are continuing to grow, especially on the northern flank of the Alps. They are prone to triggering.

Deeper in the snowpack, there are sometimes weak layers in the area of older rain crusts. However, these are often so deep in the snowpack that they are unlikely to be released by people. In southern Upper Valais, Ticino, Moesano, Val Bregaglia and Val Poschiavo, older weak layers are less covered and may occasionally be released by people.

Gliding avalanches are still to be expected, especially below 2400 m. These may become substantial, particularly on the northern flank of the Alps and in Lower Valais.

Weather forecast until Thursday, 21.12.2023

Snow will fall at times in the north. The snowfall will intensify as the day progresses. The snowfall level will be just below 1000 m at night, rising during the day to around 1400 m. In the Alpine valleys, it will continue to snow to low altitudes. It will be fairly sunny in central and southern Ticino.

New fallen snow

From Wednesday afternoon to Thursday afternoon, the following amounts of fresh snow are expected above approximately 1500 m:

• Northern Alpine Ridge from the Jungfrau region to the Alpstein: 10 to 20 cm;
• Jura, rest of the northern flank of the Alps, Lower Valais, northern Upper Valais, remaining parts of northern Grisons: 5 to 10 cm;
• less elsewhere, no snow in the south.

Temperature

At midday at 2000 m, between -2 °C in the north and 0 °C in the south.

Wind

Overnight winds will be strong, increasingly blowing at storm force during the day from the west, and from the northwest in the high Alpine regions.

Weather review for Wednesday, 20.12.2023

Clouds gathered from the northwest during the night. In the early morning, a little snow fell in the north above approximately 1200 m. It was cloudy in the north during the day. There were isolated brighter spells in the inneralpine regions and it was quite sunny in Valais and the south.

New fallen snow

5 to 10 cm of fresh snow fell along the Prealps, with less elsewhere; it was dry in Valais, Ticino and Grisons.

Temperature

At midday at 2000 m, between -4 °C in the north and +1 °C in the south.

Wind

• Overnight, winds were moderate to strong in the north, and elsewhere weak to moderate from the west.
• During the day, there were moderate to strong northwesterly winds on the Main Alpine Ridge and at high altitudes.

Trend until Saturday, 23.12.2023

From Thursday evening to Saturday afternoon, snow will fall heavily in the north. Snow will also fall widely in the other regions, with only the far south remaining dry. The snowfall level in the north will be between 1200 and 1500 m. In the inner Alpine valleys, snow will fall to below 1000 m at times. A storm force northwesterly wind will blow at high altitudes on both days.

By Saturday evening, 80 to 120 cm of snow will have fallen on the Northern Alpine Ridge from the Jungfrau region to the Glarus Alps. On the rest of the northern flank of the Alps, in Lower Valais, in the remaining parts of northern Grisons and in the Lower Engadine north of the Inn, 50 to 80 cm of snow is expected, with 30 to 50 cm expected widely elsewhere. Only a little snow will fall on the southern flank of the Alps and none in the far south. The avalanche danger will increase rapidly and significantly on Friday with heavy snowfall and stormy weather, reaching danger level 4 (high) widely on the Northern Alpine Ridge, in northern Grisons and in the Lower Engadine north of the Inn. An increase to danger level 4 (high) is also possible in Lower Valais and in other parts of Grisons. Many naturally triggered avalanches are to be expected. As the day progresses, some very large avalanches are increasingly to be expected, especially in the regions exposed to heavier precipitation. Exposed parts of transportation routes will be at risk.

The avalanche danger will also increase in the other regions. Only in the south will it remain largely unchanged.

The very critical avalanche situation will continue on Saturday, especially in central and eastern regions.