Grimselpass

Considerable avalanche danger will be encountered in some regions.

As a consequence of westerly wind, mostly small wind slabs will form at elevated altitudes. The fresh and somewhat older wind slabs are lying on top of a weakly bonded old snowpack. Avalanches can be released by a single winter sport participant. These can penetrate even deep layers and reach large size in isolated cases. Backcountry touring calls for experience in the assessment of avalanche danger.

Snowpack Snow depths at high altitudes are average for the time of year in the extreme west of Lower Valais, but below average in all other regions. At 2500 m the snow depth in western Lower Valais and in northwestern Ticino is approximately 80 cm. Elsewhere 40 to 60 cm of snow is lying over a wide area, but the amounts are smaller in some parts of central Valais and central Grisons. In particular on shady slopes above approximately 2200 to 2400 m, weak faceted layers exist deep in the snowpack over a wide area. In the west and on the main Alpine ridge from the Matterhorn into the Bernina region and to the south, these layers are already embedded so deep that even large avalanches are possible. The fresh snow and snow drift accumulations of recent days are prone to triggering in some places. Significant warming on Wednesday and the strong west to southwesterly wind will give rise to coherent, easily released snow drift accumulations formed from the fresh and old snow. Below approximately 2000 m the snowpack on the northern flank of the Alps will become moist. Observed weather review Tuesday, 13.12.2022 On Monday night the skies became overcast from the west. During the daytime it was mostly very cloudy and, in the far west in particular, a little precipitation fell until the middle of the day. Fresh snow The snowfall level was between 1000 and 1400 m. The following amounts of snow fell in the period from Monday evening until Tuesday midday:

• Extreme west of Lower Valais between Finhaut and La Fouly: 5 to 15 cm
• Central and northern Valais: a few centimetres
• Elsewhere: mostly dry

Temperature At midday at 2000 m: between -3 °C in the west to -6 °C in the east and -10 °C in the south Wind From the southwest

• In the western part of the northern flank of the Alps and on the northern Alpine ridge, moderate to strong
• Otherwise light to moderate

Weather forecast through Wednesday, 14.12.2022 It will be generally very cloudy. Brief bright spells are possible in the inneralpine regions. A little precipitation will fall in the west and north. Fresh snow The snowfall level will rise to 1800 m on the northern flank of the Alps, and to 2000 m in the west and the Jura. Above these altitudes the following amounts of snow will fall in the period to Wednesday evening:

• Extreme west of Lower Valais: 5 to 15 cm
• Rest of Valais and on the northern flank of the Alps: up to 10 cm
• Elsewhere: dry

Temperature At midday at 2000 m: between 0 °C in the north and -3 °C in the south Wind From the west to southwest

• On the northern flank of the Alps and at elevated altitudes, moderate to strong
• Otherwise mostly moderate

Outlook through Friday, 16.12.2022 Wednesday night will be clear for a time, but during the day dense cloud will build up again from the west and south. The east will remain bright as a consequence of the foehn wind. A little precipitation will fall, especially in the afternoon. In the north the snowfall level will drop to 1000 m, and in the south it will rise to this altitude. On Friday a little more precipitation will fall. In the north the snowfall level will drop to the lowlands. The wind at elevated altitudes on Thursday will remain moderate from the southwest at first; in the afternoon a bise wind will develop in the north. On Friday the bise will be moderate in the Jura, otherwise light. The avalanche danger is not expected to change significantly.