Martigny-Verbier

Considerable avalanche danger will be encountered in some regions.

As a consequence of a strengthening northwesterly wind, wind slabs will form in particular at elevated altitudes. The fresh and somewhat older wind slabs are in some cases prone to triggering. They are to be evaluated with care and prudence in steep terrain. The number and size of avalanche prone locations will increase in the high Alpine regions. Additionally in very isolated cases avalanches can penetrate near-ground layers of the snowpack and reach dangerously large size. Caution is to be exercised in particular in areas where the snow cover is rather shallow on very steep north facing slopes above approximately 2400 m.

The surface of the snowpack will cool hardly at all during the overcast night and will soften quickly. Wet avalanches are possible as the day progresses. This applies in all aspects below approximately 2400 m. Avalanches can reach large size in isolated cases in particular on north facing slopes.

Snowpack On north facing slopes above approximately 2500 m, fresh snow and snow drift accumulations are lying on loosely bonded layers; in Grisons, surface hoar has been covered with snow in some cases. Here in particular the near-surface layers are prone to triggering in some instances. On north facing slopes between 2000 and 2500 m, for the first time this winter the snowpack is becoming wet and consequently being weakened. At higher altitudes the upper layers have become moist. In Grisons in particular, in the last few days large avalanches have been released frequently in the deep, weak old snow on north facing slopes above approximately 2500 m. This danger still persists. In southern Valais and on the southern flank of the Alps, avalanches of this type can likewise not be ruled out. Observed weather review Monday, 24.04.2023 During the night a little precipitation fell over a wide area. The snowfall level was approximately 1700 m. During the day it remained mostly cloudy in the north. In the northeast in particular, a little precipitation continued to fall. The inneralpine regions were partly sunny, and the south was mostly sunny. Fresh snow From Sunday afternoon until Monday afternoon above approximately 2400 m:

• Extreme west of Lower Valais, main Alpine ridge from the Lukmanier Pass to the Bernina region: 20 to 30 cm, but locally up to 40 cm
• Grisons, central and eastern parts of the northern flank of the Alps: 10 to 20 cm
• Elsewhere: a few centimetres

Temperature At midday at 2000 m: about -1°C in the north and +2 °C in the south Wind On the northern flank of the Alps and at elevated altitudes sometimes strong, otherwise moderate; veering from southwesterly to northwesterly Weather forecast through Tuesday, 25.04.2023 The north will be very cloudy, and above approximately 1200 m snow will fall over a wide area. During the day there will be bright spells in the inneralpine regions. In the south the night will be partly clear, and during the day it will be fairly sunny. Fresh snow From Monday afternoon until Tuesday afternoon the following amounts of snow will fall above approximately 2400 m:

• Northern Alpine ridge from the Aletsch region into the St Gallen Alps: 20 to 30 cm
• Rest of the northern flank of the Alps and Prättigau: 10 to 20 cm
• Elsewhere: 5 to 10 cm over a wide area; dry in the south

Temperature At midday at 2000 m: about -3°C in the north and -1 °C in the south Wind

• Until midday moderate, at elevated altitudes sometimes strong, from westerly directions
• In the afternoon veering northwesterly, becoming increasingly strong on the main Alpine ridge and to the south

Outlook through Thursday, 27.04.2023 Wednesday The night will be clear in the south. The skies will clear early in the night in the west, but not until Wednesday morning in the east. Wednesday will be sunny at times in the north and mostly sunny in the south and east. On Tuesday evening on the main Alpine ridge and to the south, strong, sometimes storm force from the northwest, before easing significantly and backing westerly. On the main Alpine ridge and to the south, snow drift accumulations may form at elevated altitudes. Otherwise, the danger of dry avalanches will decrease. As the day progresses, wet snow avalanches originating in the fresh snow are to be expected. Thursday Wednesday night will be partly clear; in the east it will remain overcast until the morning. During the day it will be fairly sunny. It will become warmer again; the zero degree level will rise to approximately 2500 m. The danger of dry avalanches will continue to decrease. The danger of wet snow avalanches will vary during the day.