südliches Urseren

Considerable avalanche danger will be encountered over a wide area.

Avalanches can be released in the old snowpack and reach dangerously large size. Caution is to be exercised at transitions from a shallow to a deep snowpack, when entering gullies and bowls for example. Whumpfing sounds can indicate the danger. In addition further wind slabs formed during the night, in particular at elevated altitudes. The fresh and somewhat older wind slabs are in some cases prone to triggering. Backcountry touring and other off-piste activities call for experience in the assessment of avalanche danger and caution.

Snowpack At low and intermediate altitudes the snow cover on flat terrain is well below average for this time of year. At altitudes above 2500 m the snow depths are mostly slightly below average; in Valais they are average over a wide area. At 2500 m, approximately 1 m of snow is lying in northern Valais, Bedretto and the Upper Valle Maggia, and 50 to 80 cm are to be found over a wide area elsewhere; in central Grisons and Engadine 30 to 50 cm are to be found. At altitudes below approximately 2500 m the snowpack has been influenced by warm temperatures and rain; at higher altitudes and in particular in the high alpine regions it has been significantly influenced by the wind from westerly directions. In particular in Valais, the Gotthard region, Ticino and Grisons, above 2200 to 2400 m the deeper snow layers are faceted and soft. They are covered by well bonded layers of various thickness. In particular in the inneralpine regions of both Valais and Grisons, avalanches can be triggered by people in these soft old layers of snow; in the other regions, avalanches can penetrate these layers in some cases. The bonding of the snowpack is mostly a little more favourable on the northern flank of the Alps. On Monday night, however, more snow and a strong westerly wind will give rise here to fresh snow drift accumulations that are prone to triggering in some places. Observed weather review Monday, 26.12.2022 After a mostly clear night, clouds built up from the northwest during the day on Monday. Grisons remained sunny until the afternoon. Fresh snow In the west and north a few centimetres above approximately 2000 m. Temperature At midday at 2000 m: about +2 °C Wind From the west to southwest

• At elevated altitudes mostly moderate to strong

Weather forecast through Tuesday, 27.12.2022 On Monday night, precipitation will fall on the main Alpine ridge and to the north. In the morning the skies will clear from the west and in the south. In the east the precipitation will cease. In the afternoon it will be generally quite sunny. Fresh snow The snowfall level will drop from 1800 m on Monday evening to 1200 m by the time the precipitation ceases around midday on Tuesday. The following amounts of snow will fall above 2000 m:

• In the extreme west of Lower Valais on the border to France and on the northern flank of the Alps: 15 to 30 cm, but up to 40 cm locally in the eastern part of the northern flank of the Alps
• In the rest of Lower Valais and in northern Grisons: 10 to 20 cm
• Elsewhere: less than 10 cm, remaining mostly dry to the south of the main Alpine ridge

Temperature At 2000 m: between -4 °C in the north and 0 °C in the south Wind From the west to northwest

• On Monday night in the mountains, remaining strong
• On Tuesday as the day progresses, light to moderate

Outlook through Thursday, 29.12.2022 Wednesday will be quite sunny in the morning in particular, but increasingly cloudy in the afternoon. On Wednesday night a little precipitation will fall in the west. During the day on Thursday it will be mostly cloudy; but bright spells remain possible in the morning in the east, the inneralpine regions and the south. In the mountains there will be a strong southwesterly wind on Thursday in particular. It will remain mild for the time of year. The avalanche danger will decrease slowly.