The Alps are having a pretty dry start of the season. The start was promising with lots of snow in the main alpine ridge and an extremely early first PowderAlert of the season, but winter has been slacking since mid/end November. The only exception was Austria. They had some freshies, but the other countries and regions in the Alps have been (and still are) struggling. As a result, the snowcover is (a lot) thinner than normal in this time of the season.
Check out the map of Switzerland below. It shows the snow depths compared to the long term average. And that doesn't make me smile. You'll only find 30-70% of the snowcover that normally is there.
It's even sadder in the heart of the Ecrins. Resorts like the Serre Chevalier and Puy St. Vincent have a pretty dramatic start. The opening of the season is already postponed in the Serre Chevalier and when we have a look at the webcams it clearly shows that the need just a little bit more snow…A start of the winter like this happens around once every ten years and it's pretty much always caused by the lack of a southwest to west current.
The lack of this current for the last two months is pretty much the cause of the problem. Normally, depression after depression is hitting the Alps from the west, but the snow came from the north this season, with a Genua low or an Adria low as side effects.
There was already a lot of snow in the main alpine ridge in November (Verbier opened early, Tignes had great snow and the glaciers in Austria had awesome snow conditions) and these great conditions expanded into the lower regions of the Italian Piemonte and large parts of Austria. The snowcover is these regions is still pretty normal compared to the long term average. There are parts of the Dolomites that can't complain as well. But last weeks sun and the storm that hit the Alps in the beginning of December, didn't do the Alps any good. A lot of south facing slopes are green again. The wind has blown the snow away from the peaks and ridges. The great start of the season was interrupted by weather that's not particularly good for freeriding. Are we ready for some freshies? PowderAlert #6 will bring the much needed snow to the western parts of the Alps. But what about the other regions?
1. West current
The high pressure area above the Alps is breaking and quite early on Thursday morning a front will reach the western Alps. The current is westnorthwest, which normally means a lot of snow for the Jura, the western parts of Wallis, the western parts of the northern alpine ridge and the French northern Alps. The front is powerful enough to reach the Ecrins and the resorts more to the south. This first front is bringing around 5-15 centimeters (locally 20 centimeters) of snow between Thursday morning and Thursday night.
2. A second front
The second front is much more interesting. It arrives on Thursday and is coming from westsouthwest. This front is more powerful and the warm front will be overtaken pretty soon. A so-called occlusion is forming and this occlusion will drag itself really slow over the Alps. This system of fronts is sandwiched between high pressure from the east and incoming high pressure from the west. The cold air coming in from the west and the humid air coming in from the Mediterranean will form a temporary Genua low that will be sandwiched between the two high pressure areas and as a result it will drop all its snow in the (western) Alps. Especially the stau regions in the Ecrins, the Gotthard, the Mont-Blanc and Monte Rosa, the first Alps in the Savoie and the Haute Savoie, but also the complete southern French Alps and the southern Piemonte can expect a lot of freshies. You can expect around 20-50 centimeters, locally even 70 centimeters. So far, I expect the least snow in the larger resorts of the Savoie, the more ‘inner-alpine' ones, because they are in the shadow of the Ecrins. Lots of snow from Thursday afternoon till Friday. The front will travel further east after that, but don't expect more than a few centimeters.
This leads to the snow map below. I personally think that there will be more snow around the Ecrins, the French southern Alps, the first Alps in the Savoie and Haute Savoie and the resorts south of the Monte Rosa and the Gotthard than visible on the map. We'll see what the maps will show tomorrow.Source: snowmaps
3. Rising high pressure
High pressure is coming in again on Saturday. The sun will come out and the temperatures will rise.
PowderAlert #6 will finally bring snow to the French southern Alps and the other regions in the French Alps (the least snow will fall in the inner alpine resorts in the Savoie). The southern resorts in Wallis and the northern Piemonte will get freshies, just like the resorts south of the Gotthard. The result of the Alps will get some, but not much.
The long term... a white Christmas?
YES! But it will be quite turbulent. A huge low pressure area is visible on the maps for next weak. Both the models of ECMWF and GFS are expecting fireworks from the west. The weekend will be dry, but the 24th of December will be the start of a western current that will bring fronts to the Alps. This will be the start of PowderAlert #7. Too early for details, but hey, this already is positive right?