untere Maggiatäler

As a consequence of new snow and wind a high avalanche danger will be encountered in some regions.

In some places avalanches can be triggered in the weakly bonded old snow and reach medium size. As a consequence of a strong northerly wind, mostly small wind slabs will form as well. Careful route selection is recommended.

Snowpack As a consequence of intensive snowfall and strong-velocity northwesterly winds, large-sized snowdrift accumulations are being generated over widespread areas on the northern flank of the Alps, in the Valais and in northern Grisons. The enormous amounts of fresh snow and freshly generated snowdrift accumulations can trigger naturally as avalanches. In all regions of Switzerland, moreover, particularly on west-facing, north-facing and east-facing slopes above approximately 2200 m, there are expansively metamorphosed (faceted) weak layers deeply embedded inside the snow cover. As a result of the additional amounts of fresh fallen snow, increasingly frequent fractures can be expected in these weak layers. Avalanches can sweep away parts of the old snowpack and in some places the entire old snow cover. The lowermost layers inside the snow cover on south facing slopes were thoroughly wet up to over 3000 m, on west-facing slopes up to nearly 3000 m, on east-facing slopes up to nearly 2600 m and on north-facing slopes up to nearly 1800 m. As a consequence of the descending temperatures, the wet layers of the snow cover are able to freeze to some extent and incrementally stabilize. Observed weather review Sunday, 26.03.2023 Nighttime skies on Saturday were predominantly dry and, in Grisons and the Ticino, partly clear. In the early morning hours, snowfall set in from the west. The snowfall level descended from 1600 m down to 1300 m during the course of the day. Fresh snow Between Sunday morning and Sunday afternoon, the following amounts of fresh snow were registered above approximately 1800 m:

• northern and furthermost western parts of the Lower Valais: 30 to 40 cm, as much as 50 cm from place to place;
• remaining regions of the northern Alpine Ridge west of the Reuss: 15 to 30 cm;
• remaining parts of the northern flank of the Alps, remaining parts of the Valais, northern Grisons, Lower Engadine north of the Inn: 5 to 15 cm;
• in the other regions of Switzerland, less.

Temperature At midday at 2000m, -2 °C. Wind Winds were blowing at moderate to strong velocity from westerly directions. Weather forecast through Monday, 27.03.2023 On Sunday night, snowfall over far-reaching areas is anticipated which will be particularly intensive in the Valais and on the northern Alpine Ridge. The snowfall level will descend down to low lying areas during the nocturnal hours. During the daytime, additional snowfall is anticipated in the northern regions and in the Valais. In the furthermost southern regions it is expected to be quite sunny. Fresh snow Between Sunday evening and Monday afternoon, the following amounts of fresh snow are expected above 1500 m:

• northern Alpine Ridge from the Trient region into the Glarus Alps, Lower Valais: 30 to 50 cm; in the eastern part of the Bernese Oberland and in the central sector of the northern flank of the Alps as much as 60 cm;
• remaining parts of the northern flank of the Alps, southern part of Upper Valais not including the southern Simplon region, as well as the Gotthard region, northern Grisons, Engadine north of the Inn: 20 to 30 cm;
• western part of Jura region, southern Simplon region, central Grisons, remaining parts of Engadine: 10 to 20 cm;
• in the other regions of Switzerland, less; or else it will remain dry.

Temperature At midday at 2000 m, between -9 °C in the northern regions and -5 °C in the southern regions. Wind Winds will be northerly to northwesterly,

• on the Main Alpine Ridge and southwards therefrom, blowing at strong to stormy velocity;
• in the other regions of Switzerland, blowing at moderate to strong velocity.

Outlook through Wednesday, 29.03.2023 Tuesday On Monday night the snowfall will come to an end, to start with in the western regions, in the early morning hours on Tuesday also in the eastern regions. Apart from residual clouds in the eastern regions it is expected to be quite sunny. During the afternoon, high-altitude clouds will move in from the west. At high altitudes a moderate-strength northwesterly wind will be blowing. The danger of dry-snow avalanches will incrementally decrease, nevertheless isolated naturally triggered dry-snow slab avalanches are still possible, including large-sized releases. Furthermore, numerous loose-snow avalanches can be expected to trigger from the fresh fallen snow on sunny slopes. Wednesday On Wednesday in the northern regions, skies are expected to be variably cloudy. Above approximately 2000 m a small amount of snowfall is possible. In the southern regions it will be quite sunny. A moderate-strength westerly wind, blowing intermittently at strong-velocity at high altitudes, will prevail. The zero-degree level is expected to ascend to approximately 2000 m. The danger of dry-snow avalanches will decrease, nonetheless only gradually on shady slopes at high altitudes. As a consequence of solar radiation and higher daytime temperatures, wet-snow and gliding avalanches are possible.