A pattern is emerging this (late) early winter. Changing fronts from the west, bringing sometimes cool, sometimes mild and humid air to the western slopes of the Alps. As with the Dumpicane, this is now the case again. After a few insignificant flakes of up to 10 cm today (an exception in Switzerland with 25 cm), it will start tomorrow (30.12.2011).
The first front will arrive from the northwest and snow will start to fall from the Hautes-Alpes to the Arlberg. It will also accumulate further east to the Dachstein due to the incoming flow. By Friday evening, 20-40 cm is possible across the board, in the very west of France it may look like a little (10-20 cm) more, but this is not yet set in stone. The snow line is at the very bottom. Treeskiing in congested areas is therefore advisable. Save the nicer lines for the afternoon, as there will be more snow then.
At night, the current turns to the west and it gets milder. On New Year's Eve, the snow line will rise to 1500-1800 m with a new intense warm front, with the higher limits further west and outside the Alps. I can't say whether it will snow up to 1000 m or lower in Aosta, Valais and inner Alpine valleys further east. It all depends on the intensity of the precipitation and to what extent the cold on the ground proves to be tough.
Powder for the Prosit New Year
Another 35-50 cm is expected from France to the Arlberg for the "Prosit New Year", depending on the accumulation. Further east it will also be milder, but the amounts on New Year's Eve are rather modest, as with the Dumpicane. If it gets 10-20 cm, you can be happy. Unfortunately, the areas in the north will not turn to the north now, so there will be no northerly accumulation like after the Dumpicane.
On New Year's Eve, it is expected to be mild and calm with some clouds and you can then go to the high mountains to sober up and see where Ullr has sent the white splendor.
Sum of fresh snow until New Year
All in all, 50-90 cm from the Aiguille du Croissant to the Mooserwirtspitze by New Year, although the "90" is more likely to be found in France, if at all. I don't want to rule out the magic meter in isolated cases, but since I'm unlikely to be surprised by an intense accumulation here and the models generally capture such large-scale precipitation quite well, I think the meter will hardly be exceeded.
Towards the main Alpine ridge and in the south, of course, correspondingly less to zero. Positive surprises are again possible in Valais and Goms. If the precipitation behaves analogously to the Dumpicane, the amounts of the northwest/west jam can almost be reached there. However, it is not possible to say exactly whether it will push in like this again. The intensity levels may also be too low. East of the Arlberg, a maximum of 30-50 cm is possible, as there is hardly anything left on New Year's Eve and it rains in at the bottom anyway. For Italy (except Courmayeur), however, it's still: Carvon con pisto Italiano because nullo neve polverosa in Fuoripista.
Outlook
The development after that is still completely unclear, but if there's internet fondue in Valais, I'll dip my oracle wand in and let you know about Ullr's possible blessings again on New Year's Day.
Powder to the people!
Text: Lars Oelmann