Transition to stable high pressure weather

The last dump of this wet week is still ongoing in the Western Alps. Today, we look at what all the variability has brought and where the most powder has fallen. We also look ahead to the coming week, which will be dominated by a powerful high-pressure area.

Last snow for a long time

This morning, Austrian areas south and east of Salzburg still benefited from snow showers. Regionally, 15 centimeters fell during the night and morning. The dump for which we issued Powder Alert 3 this week is still ongoing and will bring more snowfall in the evening and night in southern Switzerland, NW Italy, and the French Alps. From the west, mild air is flowing in, causing the snow line to rise to around 1800 meters in France and 1500 meters in Switzerland and Italy. So far, 30 to 60 cm has fallen at higher altitudes since yesterday, with another 10 to 20 cm expected regionally tonight.

Precipitation rich week almost over, great conditions above 1800 meters in France and Switzerland

A series of depressions kept meteorologists and winter sports enthusiasts busy this week. As expected, most precipitation fell in the Western Alps, and below 1800 meters, it also led to a lot of rain regionally. The graph above shows the precipitation in Flaine (1611 m), where nearly 80 mm of precipitation fell in 3 days, an amount that normally falls in 3 weeks. If it was colder, this could have produced almost a meter of snow, but the snow cover actually shrank from 50 to 40 centimeters during this period. Only above 1800 – 2000 meters has the snow depth increased significantly. The best conditions in terms of fresh snow are found from that height, where the base in France and Switzerland is now 1 to 2 meters thick in most places. Due to the strong wind, the thickness varies greatly, with wind-sensitive peaks being almost bare and the best snow found on leeward slopes. In Austria and Italy, the snow line was lower this week, but less precipitation fell than expected. The best conditions are found here from 1800 meters in Vorarlberg. In Austria and the entire Southern Alps, there is still significantly less snow than normal in most regions.

Cold weekend with strong winds

The high-pressure area that will ensure a long stable period has an extension to Norway this weekend. As a result, the Alps will be in a northerly flow with cold upper air. You will notice this most if you are in Austria or eastern Switzerland, where it freezes down to the valleys. South of the main ridge an icy northeasterly wind may can lead to lift closures regionally, especially on Sunday. At 2000 meters, it will not get warmer than -10, and at night it will freeze severely to very severely (below -15) in the valleys. In the Western Alps, it is much less cold during the day, with 0 to -5 at 2000 meters. There are significant sunny periods, and especially Austria remains sensitive to a light snow shower north of the main ridge.

Sunny and milder next week

After the weekend, the high-pressure area will move south, allowing milder air to flow in. The weather will remain clear, and it will still freeze almost everywhere at night. There is still uncertainty about how mild it will get, and fortunately, we now see fewer extremely mild members in the ensembles. In the GFS ensemble for Innsbruck above, it’s clear that the temperature at 1500 meters will only rise to an average of +4 by the end of the week. In the Western Alps, it will be a few degrees milder. It is the usual “high-pressure thaw,” where the snow will remain fluffy for a long time due to very low humidity. South-facing slopes will become soft in the afternoon, but this can also be an advantage in places where the snow cover is already harder or older. We do not expect any significant precipitation until at least January 20.