144 cm of fresh snow already, but the biggest dump is still coming!


By meteomorris on 22 November 2016 · 0

Are you a pessimist? Or are you an optimist? Yes, it is mild, it's raining in the valleys, there's a strong Föhn on the north side of the Alps, the snow line is rising and all the snow that came down in the beginning of November is disappearing from the valleys and mid-mountain. But it's only November 22nd, the snow cover in the high alpine is already thicker than last year, there's plenty of snow coming down in the high alpine of the southern Alps and the snow line will drop again on Thursday and Friday. As you can see: I'm an optimist. But I am not the kind of optimist that turns this mixture of snow and rain into a PowderAlert. More positive: the snow that comes down in the high alpine is here to stay and forms the base for the rest of the winter. It's better to have a thick snow pack right now, than a layer with sugar snow that will result in a higher risk of avalanches later in the season. In this forecast:

  • Why is the weather that mild?
  • Already 144 cm of fresh snow (and 30-90 cm of snow on average)
  • The biggest dump is still coming
  • Cold snow on a warm base
  • Long term: colder?

Why is the weather that mild?

It's just a matter of bad luck. If the Alps were positioned 1000 kilometers to the west, they had to deal with cold air. The jet stream goes up and down and as a result she'll bring cold air far to the south, but she could also bring warm air to the north. The Alps were in the middle of the cold air in the beginning of December, right now it's warm air all over the place. Simply bad luck.

You can check it out on the maps below. The jetstream is the shifting red line and functiones as a conveyor belt for storms going to Europe. It's warmer on the left and right of the V and the U that the jetstream is creating. It's cold in the middle. You can see that on the map below. It's cold in the V (green) and on the left and right end side of the V it's warm.

Jet stream is meandering
Jet stream is meandering

Green is cold, orange is warm
Green is cold, orange is warm

Already 144 cm of fresh snow (and 30-90 cm of snow on average)

The air that's arriving in the Alps is pretty warm and the freezing level should be around 2500 to 2700 meters if there weren't any mountains. But fortunately for us the proscess of clouds pushing and the condensation releases a lot of energy, causing the air to cool down locally and causing the snow line to drop to 2000 meters or lower. Especially in the areas where the clouds are forced to rise it's snowing heavily, but the temperature will also drop and the snow line will end up at 2200 meters or even lower.

Between 50 and 90 cm of snow (locally almost 150 cm of snow) came down in the regions where they had the most precipitation on the south side of the Alps (French southern Alps, Tessin in Switzerland and the Italian Piedmont). It's not that the snow cover grew a solid meter everywhere, but the fresh snow makes the snow cover grow around 30-70 cm.

Up to 144 cm of fresh snow
Up to 144 cm of fresh snow

You can see that the snow line is dropping locally on this image from Champorcher, a resort in the northwest of Italy. The trees at an altitude of 1900 meters are white this morning!

Champorcher
Champorcher

Gressoney
Gressoney

The biggest dump is still coming

In my forecast from yesterday you could read that the current is turning to the east to southeast tomorrow and that we can get ready for the famous retour d'est (snow from the east). The current is turning slowly but surely. It's getting weaker at first and the push of the clouds won't be that strong anymore. The result is that the snow line will rise to 2000 - 2200 meters today and Wednesday. The snow line will drop again to 1800 meters or lower in the night to Thursday. Cold snow will come down above 2000 meters. You can expect the temperatures to be the lowest on the Italian side of the border (thanks to the push of the clouds), but the snow line on the French and Swiss side will be 200 to 300 meters higher.

TIP: Check out our detailed map for Thursday

Huge amounts of snow on Thursday
Huge amounts of snow on Thursday

Cold snow on a warm base

The good thing of a dropping snow line is that cold snow will fall on a warmer and compact base. The advantage is that you won't sink that deep, but you have the fluffy pow on top. But only in the resorts where it's actually snowing on Thursday. It's simply too warm in the rest of the Alps.

Long term: colder?

When all the precipitation comes to an end at the end of the week, we can get ready again for some cold air from the north of Europe. Don't expect any more snowfall soon, but there's definitely some snow on the maps for the near future. You'll find a good base for the rest of winter in the high alpine by the end of the week and King Winter should start with bringing plenty of snow to the pre-Alps in the beginning of December. More details about where to ride powder this weekend on Thursday!

Stay stoked. Morris


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