PA#23: up to 150 cm of freshies


By meteomorris on 19 March 2014 · 0

Searching for pow at the Arlberg (through PowderQuest App)

Update Thursday 7.35. The models are indicating a longer period with cold temperatures. This will be the dump you don’t want to miss if you want to ride some powder. Monday to Friday will be really good. More details tomorrow (Friday)! Wax up!

The day starts with strong winds today (Wednesday) in Austria. The temperatures drops to normal numbers for the time of the year. But it's only for a short periode of time, because it will be warm again tomorrow. The temperatures go up to a dazzling 20+ degrees in the valleys on Thursday and Friday. It's summer in the mountains (again) with temperatures normal for mid June. Our warning for wet snow avalanches is still in effect. The image below of a huge wet snow avalanche in Livigno speaks for itself.

It's too warm till Saturday and you'll have to watch out. The snow is getting colder during the nights, but the risk increases during the afternoon when wet snow avalanches become an instant problem. It will last till the weekend before winter kicks in again.

Megastorm Hannelore
Megastorm Hannelore

Megastorm Hannelore

It's only Wednesday and we'll have to wait till Saturday before the first snow will fall. But the low pressure area that will cause it to snow is ready and waiting above the Atlantic. Her name? Hannelore. She has some trouble pushing the high pressure area Johannes from the maps. If you have a look at the jet stream maps, you can see how slow the jet stream moves from the Atlantic to the Alps. It will last till Sunday before the jet stream reaches the western parts of the Alps. The jet stream forms the division between warm air form the south and cold air form the north. And the precipitation will be intense on the location where the cold air and warm air finally meet. Especially when there's a mountain region with peaks up to 4000 meters in the way.

Jetstream above the western Alps
Jetstream above the western Alps

If you have a look at the jetstream you can see the arrows coming in from the south. Normally this means snowfall from the southwest. This is confirmed by the so-called Föhn chart. We'll have to deal with a southern Föhn till Saturday, colder air will come in from the west after Saturday.

Southern Föhn
Southern Föhn

It's good to know that the Föhn chart above is valid for the line Luzern-Lugano. This is where the jet stream will have his hangout this weekend. If we look further east (Dolomites and Austria), it looks like the jetstream won't get any further than the line Innsbruck-Bolzano. A rapidly growing high pressure area above Russia is blocking the jet stream and forces it to move north.

Jetstream is blocked and resolves
Jetstream is blocked and resolves

As a result, the Alps have to deal with high pressure again and there's no such thing as cold arctic air any more. PowderAlert #23 will be intense, short, but will result in lots of snow for the higher alpine.

High pressure north of the Alps form Tuesday

So, what does this all mean?

This was the conclusion on Monday: The temperatures will go down, and there'll definitely be some freshies in the higher alpine from Sunday. It's about time for some nice lines in the higher alpine next week. Don't go out to the resorts in the first mountains of the Alps and avoid resorts where the peaks are not higher than 1500-1800 meters. It's time to focus on the inner alpine resorts and the main alpine ridge. There's plenty of snow here and the higher temperatures last week and this week will cause a lot of wet snow avalanches. The new snow coming in on Sunday and Monday will bring nice touring conditions and it's time for the big lines and couloirs.

And it's just like that. The jet stream is parked above Switzerland on Saturday and Sunday, so I expect the most freshies here. But don't think it will be a powder day on Saturday. The colder temperatures are coming in very slowly and it's hard to say when that will happen exactly. The battle of the storm Hannelore and the high pressure area Johannes isn't to be determined exactly (yet) in terms of centimeters. A shift to the east or the west could have some consequences, but in short, you can expect the following:

Friday: Warm in the complete Alps, but you can see some high clouds coming in in the western Alps. It will start snowing in the French Alps in the night from Friday to Saturday. Especially south of the Ecrins, with a snow line around 1500 meters.

Saturday: The jet stream is moving east. The current is still southwest. Most snowfall south of the Ecrins in France en south of the line Monte Rosa - Gotthard - Piz Bernina. The snow line in the French Alps will drop to a 1000 meter. Cold air will enter the western Alps in the night from Saturday to Sunday.

Sunday: The jet stream is moving further east and will stop at the line Innsbruck - Bolzano. The precipitation will be intense in Switzerland, where you can expect around 150 centimeters of freshies around the Gotthard, Monte Rosa and the northern Swiss alpine ridge. It will also snow in the French Alps and west of Innsbruck in Austria. The snow line in France, Switzerland, the Italian Aosta, Piemonte and Lombardia will drop to 700-1000 meters in the night. More to the east the snow line will be around 1000-1500 meters.

The snowfall will be pretty intense, so Monday will be a great day for tree runs in resorts that already have a good base between the trees. It will be dry and warm and it's about time to ride some nice lines in the higher alpine. The weekend comes to early for this PowderAlert, but it will be great from Monday. More details on Friday.

Conclusion

Hang in there. Treeruns on Monday and up to the higher alpine after that. Check out the video below for some inspiration. An instant classic!

Stay stoked

Morris


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