It's pumping! And in hurricane-force winds! The appropriate name for the upcoming system for freeriders would be: Dumpicane. As our PowderGuide weather expert, the only one who really knows her stuff, has already explained how it comes about (WeatherBlog for Freeriders 07/2012), here's what it means for us. It's "dumpt"!
The amounts of the days so far are enormous and already from Tuesday to today (Thursday, 15.12.) over 50-60 cm have fallen in places in the west.
Predicting a system like this is extremely difficult and the models are still fluctuating back and forth even now in terms of the track. But, and this is the good thing, the precipitation forecasts are robust. That means it will dump, and not in short supply. Praise Ullr! I'm dividing the upcoming period through Sunday into two parts: today through Saturday morning, which is the core of the dumpicanes, and the following northwest dumping.
Part 1 - Dump to the hilt
The colorful maps and the warnings from professional colleagues hint at it: The volumes are huge. From today until Saturday noon, I expect the following amounts in France from the Oisans to the north and in the west of Switzerland to the lower Valais: We should easily get 70-100 cm over a wide area. In extremely congested areas, 120 to 150 cm could also accumulate. However, this is the maximum amount I can see and it will only be reached very occasionally, if at all. However, I don't see the total of "almost 2 m" from our model (To the PG fresh snow forecast), as the model's height bias is too generous here. You notice that it always snows the most on Mont Blanc ;). The strength of the storm will also push the precipitation far into the otherwise low precipitation central Valais, so I think 40-70 cm is also possible there, in the Goms, in the Bernese Oberland and on the central northern slopes of the Alps. Possibly even more in Valais or Goms as these effects are difficult to estimate due to the precipitation pushing in from the west.
From the central northern slope of the Alps to the Arlberg, 25-50 cm should be possible. Less in the regions shielded from the west. More on the Arlberg and in Glarnerland.
Further east and south it will be less and it could be a maximum of 0-30 cm, although the models on the Dachstein also give more, which I can't imagine. But dear Eastern Alps: There is at least some model hope.
Initially, the snow line will be around 1500 m, but should plummet from midday on Friday and there will be snow all the way down at the weekend. That means: cold smoke on top. At least where there's no wind and it doesn't pile up into 4-meter-high drift snow packs.
Part 2: The northwest accumulation
The models tend to underestimate the following northwest accumulation and despite the rather poor forecasts from Saturday morning to Sunday evening, I predict 20-40 cm from Chamonix to the Dachstein in the north/northwest accumulation areas. In the south of the main Alpine ridge and in Valais, however, none of this will arrive and the amounts will also rapidly decrease in France south of Grenoble. But I'm going out on a limb here, because even our Dumpicane is not yet completely clear and therefore the subsequent development is not entirely trivial. I won't say anything about the other trends, because it's completely unclear what will happen from Monday. If I emerge from the powder with my snorkel, there will be a new alert on Sunday or Monday.
Where would I ride and when? I won't tell you, but I'd hide deep in the trees on Friday to avoid being blown away and Saturday/Sunday is also rather poor visibility with snowfall in the north. However, there may be one or two weather windows, especially in the inner Alps, so you can also visit ski areas that offer trees and terrain.
Pay attention to the avalanche danger, read the bulletins and take it slow. The wind is monstrous!
Powder to the people!
Text: Lars Oelmann