Gruyère

Snowpack

The snowdrift accumulations that have formed in the last few days with sometimes strong northeasterly winds are still prone to triggering in places. With moderate winds from southwesterly directions, fresh snowdrift accumulations will form on Sunday, especially in the north at high altitudes.

Deeper in the snowpack, there are faceted weak layers prone to triggering, especially on shady slopes above approximately 2400 m and generally in the high Alpine regions. Avalanches may also be triggered in these deeper layers in places.

Outlook

In the west, 70 to 100 cm of new fallen snow is expected from Sunday evening to Tuesday evening. Up to 110 cm will fall locally, especially in the extreme west of Lower Valais on the border with France. On the central and eastern parts of the northern flank of the Alps, 40 to 60 cm of new fallen snow is expected, locally up to 70 cm. In Grisons and on the northern flank of the Alps, the amounts of new snow expected are appreciably smaller.

On Sunday evening, the snowfall level will increase rapidly to 1500 m, especially in the west, before dropping to 900 to 1100 m on Monday. On Tuesday, the snowfall level will drop to low altitudes. From Sunday evening to Monday evening, this event will be accompanied by strong to stormy westerly to southwesterly winds. During the night into Tuesday, the wind will shift to the northwest and will decrease.

With intense snowfall and stormy southwesterly winds, the avalanche danger will increase on Monday in the west and north, and significantly in the west. The extreme west of Lower Valais will reach danger level 4 (high) during the course of the day. In the regions exposed to heavier precipitation, more naturally triggered avalanches are to be expected. At high altitudes, these may also sweep away deeper, weak layers of the snowpack and may occasionally become very large, especially on north-facing slopes. Exposed parts of transportation routes may be at risk. Snow will continue to fall on Tuesday, especially on the northern flank of the Alps. Danger level 4 (high) may also be reached in some regions along the northern Alpine ridge.