Avers

Snowpack

After mild weather, overcast nights and some rain, the snowpack has become increasingly water-saturated over the last few days. On southern slopes, the snowpack is water-saturated up into the high Alpine regions, while on eastern and western slopes, the majority is water-saturated up to around 2800 m. On northern slopes, water saturation is under way up to altitudes of around 2400 m. There has been particularly high wet snow avalanche activity on northern slopes in recent days.

Given the southerly winds and expected volumes of fresh snow, large snowdrift accumulations will form at high altitudes. Breaks in the old snowpack are possible in particular on northern slopes where there are increasingly large volumes of overlying snow. This is especially the case in southern Valais, Ticino and in some regions in Grisons, where there are faceted layers deeper in the snowpack, but also in isolated cases in other regions.

Weather forecast to Wednesday

Overnight to Wednesday, precipitation will intensify in the south and increasingly extend into the Bernese Oberland over the course of the day. The snowfall level will be between 2000 and 2200 m and, from midday, will drop from the west. Conditions will remain dry in the northeast and there will be clear spells.

Fresh snow

Snowfall above approximately 2200 m by Wednesday afternoon:

• Monte Rosa region, Saas valley, Simplon, Binntal, Bedretto, upper Valle Maggia: 80 to 120 cm, and locally more;
• rest of Main Alpine Ridge from the Great St. Bernard to the Lukmanier Pass, Northern Alpine Ridge from the Lötschental to the Susten region, lower Valle Maggia, Leventina: 40 to 80 cm.
• rest of Valais, rest of the Northern Alpine Ridge west of Tödi, Main Alpine Ridge from the Lukmanier Pass to the Bernina region and south of there: 15 to 30 cm.
• elsewhere a few centimetres or dry

Temperature

At midday at 2000 m between 0 °C in the northwest, +4 °C in the south and +7 °C in the east

Wind

• Strong to storm force southeasterly at high altitudes
• Strong foehn wind in the north, especially overnight to Wednesday

Weather review for Tuesday

Conditions were very cloudy overnight and precipitation set in on the southern flank of the Alps, which for a time also extended to the northern side of the Alps. The snowfall level was 2000 m in the south and 2200 to 2400 m in the north. During the day, conditions were initially overcast, with clear spells developing in the afternoon in the north.

Fresh snow

Snowfall above 2400 m by Tuesday afternoon:

• central part of the southern flank of the Alps and Val Bregaglia: 10 to 20 cm.
• rest of Main Alpine Ridge: 5 to 10 cm; elsewhere: less or dry.

Temperature

At midday at 2000 m between +1 °C in the south and +5 °C in the north

Wind

• Moderate to strong southeasterly at high altitudes on the northern Alpine ridge
• In the north, moderate foehn wind from the south at times
• Otherwise mostly light to moderate from southerly directions

OutlookThursday

Precipitation will remain persistent and heavy and will only subside appreciably from Thursday afternoon. A further 100 to 150 cm of snow is expected in southern Upper Valais, and around 50 to 100 cm in the rest of Valais and on the Northern Alpine Ridge west of the Reuss. The snowfall level will drop significantly from the northwest to around 1200 m. On the central part of the southern flank of the Alps, it will remain at around 2000 m, while in Valais it is expected to drop to 1600 to 1800 m. The southeasterly wind will remain strong at high altitudes for the time being. Avalanche risk will increase to high (level 4) in widespread areas of the west and south. Level 5 (very high) cannot be ruled out in those regions exposed to heavier precipitation.

Given the rainfall, many medium and large wet snow avalanches are to be expected, especially on north-facing slopes. With increasing amounts of fresh snow at high altitudes, avalanches may also start in the dry snowpack. Breaks deep in the old snowpack are also to be expected. Very large avalanches will then advance along the usual avalanche tracks to intermediate altitudes and thus far into snow-free terrain. Extremely large avalanches are also possible from the second half of the night on Thursday, especially from north-facing, high-altitude starting zones. As the precipitation subsides, the peak of avalanche activity is expected to have passed by Thursday afternoon.

Friday

There will still be a little precipitation and temperatures will continue to fall somewhat. Winds will drop significantly. Avalanche risk will decrease. However, naturally triggered dry avalanches are still possible, while dry and wet avalanches, which may also become large, are to be expected primarily in the west in the sunny conditions.