New snow
- Above 2,200 m
Snowpack
After mild weather, overcast nights and rain in some regions, the snowpack has become increasingly water-saturated in recent 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.
With large volumes of fresh snow and southeasterly winds, large snowdrift accumulations are forming above around 2500 m. This overlying snow can be expected to cause fractures in the old snowpack, in particular on northern slopes. This is especially the case in southern Valais, Ticino and in some regions of Grisons, where there are faceted layers deeper in the snowpack, but also in isolated cases in other regions.
Precipitation will be exceptionally heavy from Wednesday to Thursday midday in those regions most exposed to precipitation, causing a rapid increase in avalanche risk, especially overnight to Thursday.
Weather forecast to Thursday
Precipitation in the south and west will remain very heavy until midday on Thursday. The snowfall level will be between 1400 and 1600 m on the western part of the northern flank of the Alps and in Lower Valais, between 1600 and 2000 m on the central part of the northern flank of the Alps and in Upper Valais, and between 2000 and 2400 m on the central part of the southern flank of the Alps and in central and southern Grisons. In the northeast, conditions will remain mostly dry and there will be clear spells, both overnight and during the day.
Fresh snow
Snowfall above around 2400 m by Thursday afternoon:
Temperature
At midday at 2000 m between -2 °C in the northwest, +2 °C in the south and +5 °C in the east
Wind
Weather review for Wednesday
Precipitation became heavier in the south overnight to Wednesday, and then increasingly extended into the Bernese Oberland over the course of the day. The snowfall level was between 2200 and 2400 m on the central part of the southern flank of the Alps and between 2000 and 2200 m elsewhere. In the northeast, conditions were dry with sunny intervals.
Fresh snow
Snowfall above 2400 m from Tuesday to Wednesday afternoon:
Temperature
At midday at 2000 m between +1 °C in the northwest, +3 °C in the south and +7 °C in the east
Wind
Outlook
Temperatures will fall on Good Friday and there will be little precipitation. There will be sunny intervals in the west and still mostly cloudy conditions in the east. Winds will drop significantly. The risk of dry avalanches will decrease. However, the situation is likely to remain critical for snow sports participants. The risk of wet avalanches will also decrease, although moist and wet avalanches from the fresh snow are to be expected, especially in the west, with higher daytime temperatures and sunshine.
On Easter Saturday, conditions will be mainly overcast in the south, but there will be little precipitation. In the north, conditions will be mostly sunny and milder again. There will be light to moderate winds from southerly directions. Avalanche risk will decrease further and will be increasingly subject to daytime changes, especially in the north.
Bulletin data: WSL Institute for Snow and Avalanche Research SLF (CC BY 4.0)