nördliches Prättigau

In Grisons a high avalanche danger will be encountered in some regions.

Large quantities of fresh snow and the wind-drifted snow are lying on top of a weakly bonded old snowpack in all aspects. Single winter sport participants can release avalanches very easily. Remotely triggered and natural avalanches are to be expected. Avalanches can penetrate near-ground layers of the snowpack and reach large size. The danger exists primarily in alpine snow sports terrain. Avalanches capable of reaching valley bottoms and endangering exposed transportation routes are unlikely to occur. Whumpfing sounds and the formation of shooting cracks when stepping on the snowpack can indicate the danger. The conditions are critical for snow sport activities outside marked and open pistes.

Snowpack The anticipated fresh snowfall is being deposited in wind-protected terrain distant from ridgelines on top of an unfavourable, expansively metamorphosed (faceted) and loosely-packed old snow cover over widespread areas. At elevated altitudes the snowpack surface shows pronounced influences of northwesterly wind impact during the last few days and is more favourable. More deeply embedded inside the snow cover in the region extending from the southern Valais over the Gotthard region as far as Grisons there are numerous softened, expansively metamorphosed (faceted) layers evident between consolidated layers of snow and crusts. The faceted layers are especially pronounced in places where the snowpack is shallow and where one sinks down to the ground on skis. On the northern flank of the Alps, the lowermost part of the snowpack is frequently well consolidated; nevertheless, above that section there are several expansively metamorphosed (faceted) layers embedded in the snowpack. In the northern and the furthermost western part of Lower Valais, the snowpack layering is most favourable and there are hardly any pronounced weak layers evident. Observed weather review Friday, 03.02.2023 On Thursday night in the eastern regions, there was a small amount of fresh snow registered. During the daytime hours on Friday it was predominantly sunny. Fresh snow - Temperature At midday at 2000 m, between +3 °C in the western and the southern regions and -1 °C in the eastern regions. Wind Winds were northwesterly,

• in the western regions blowing predominantly at light to moderate strength;
• in the remaining regions of Switzerland, blowing at moderate to strong velocity at elevated altitudes; in ridgeline terrain and in pass areas, blowing intermittently at storm strength.

Weather forecast through Saturday, 04.02.2023 On the Main Alpine Ridge and northwards therefrom, skies will be heavily overcast accompanied by precipitation, particularly in the central and eastern sectors of the northern flank of the Alps and in northern Grisons. Bright intervals are possible in the Valais and in the Engadine more than anywhere else. Fresh snow The snowfall level will lie between 1000 and 1300 m, in the Alpine valleys also lower down in some places. The following amounts of fresh fallen snow are anticipated:

• from the eastern Bernese Oberland into the Alpstein region, Prättigau, Silvretta, Samnaun: 20 to 40 cm;
• from the Aletsch region into the Haslital, in the remaining parts of the central and eastern sectors of the northern flank of the Alps and in central Grisons: generally 10 to 20 cm;
• in the other regions of Switzerland, less; on the southern flank of the Alps it is expected to remain dry.

Temperature At midday at 2000 m, between -2 °C in the western and the southern regions and -6 °C in the eastern regions. Wind Winds will be blowing from northerly directions,

• in the western regions at moderate strength, at strong velocity at elevated altitudes;
• in the eastern and the southern regions blowing at strong to storm strength.

Outlook through Monday, 06.02.2023 On Sunday in the Valais, on the southern flank of the Alps and in the Engadine, it is expected to be quite sunny. In the northern regions, skies will be bright only in the morning hours, later in the day heavily overcast as precipitation in the eastern regions sets in. During Sunday night, snowfall is expected over widespread areas on the northern flank of the Alps and in Grisons, extending down to low lying areas. However, only a small amount of fresh snow is anticipated. During the daytime on Monday, it will be predominantly sunny over far-reaching areas. Winds on Sunday will still be blowing at strong velocity from northerly directions in many places, subsequently on Monday the winds will slacken off further. The avalanche situation will remain critical for winter sports enthusiasts, particularly in the areas where snowfall is heaviest.