Martigny-Verbier

For those venturing off piste a critical avalanche situation will prevail.

Snowpack Fresh snow and a strong northwesterly wind have given rise to extensive snow drift accumulations over a wide area on the northern flank of the Alps and in Valais and northern Grisons. On Monday night they will become a little larger still in the north and east. In all regions, in addition, in particular on west, north and east facing slopes above approximately 2200 m, weakly bonded, faceted layers that are prone to triggering exist within the snowpack. Avalanches can release parts of the old snowpack and in some places the entire snowpack as well. Observed weather review Monday, 27.03.2023 On Sunday night, snow fell over a wide area except in the far south; in the north the snowfall was heavy. During the day the snowfalls were showery and there were isolated bright spells. The snowfall level was 1000 m during the night before dropping to between 500 and 700 m during the day. In the far south it was mostly sunny with a north foehn. Fresh snow From the onset of the precipitation on Sunday morning until Monday afternoon, the following amounts of snow fell above approximately 1800 m:

• Extreme west of Lower Valais, northern Alpine ridge from Les Diablerets into the Glarus Alps: 40 to 60 cm, but locally up to 70 cm
• Other regions on the northern flank of the Alps excluding the Prealps, rest of Valais excluding the southern Simplon region, rest of the Gotthard region, northern Grisons, northern Lower Engadine: 20 to 40 cm
• Southern Simplon region, northern Ticino excluding the Gotthard region, and in the eastern part of the main Alpine ridge and the neighbouring regions to the north: 10 to 20 cm
• Further south: a few centimetres, but none in Sotto Ceneri

In the Prealps and the Jura 10 to 20 cm of snow fell above approximately 1400 m. Temperature At midday at 2000 m: about -7 °C in the north and -5 °C in the south Wind

• Moderate to strong, in the high Alpine regions strong to storm force at times from the northwest
• In the south moderate, in the upper Alpine valleys occasionally strong north foehn

Weather forecast through Tuesday, 28.03.2023 On Monday night a little more snow will fall in the north and east, even at low altitudes. The snowfall will cease first in the west, and in the morning in the east as well. Apart from residual cloud in the east, it will be mostly sunny. In the afternoon, high-altitude cloud will build up from the west. Fresh snow From Monday evening until Tuesday morning above 1000 m:

• Northern flank of the Alps from the eastern Bernese Alps into the Glarus Alps, northern Grisons, northern Lower Engadine: 10 cm, but locally up to 20 cm
• Elsewhere: a few centimetres, dry in the south

Temperature At midday at 2000 m: between -2 °C in the west and -6 °C in the east Wind At elevated altitudes and in the south on Monday night, remaining strong, otherwise mostly moderate from the west to north Outlook through Thursday, 30.03.2023 In the north on both days there will be variable cloud with light precipitation but some sunny intervals as well. The south will be partly sunny. Temperatures will rise. The snowfall level will be approximately 1800 to 2200 m. The wind from westerly directions will be moderate to strong in the north, and light to moderate in the south. The danger of dry avalanches will decrease, but only slowly on shady slopes at high altitudes. Under the influence of solar radiation and warming, on each of the coming days both wet snow and gliding avalanches can occur as the day progresses.

The new snow and wind slabs of the last few days are prone to triggering. Single winter sport participants can release avalanches easily. In particular on steep west, north and east facing slopes they can be released in the weakly bonded old snow and reach large size. Individual natural avalanches are possible. Whumpfing sounds can indicate the danger. Backcountry touring and other off-piste activities call for experience in the assessment of avalanche danger and restraint.

As a consequence of solar radiation moist snow slides are to be expected as the day progresses.