PowderAlert #14: Lots of freshies for the high alpine!


By meteomorris on 30 March 2016 · 3

Interesting days in and around the Mediterranean are ahead of us. A large low pressure system triggers a strong southern current causing a stormy Föhn and lots of precipitation on the south side of the Alps. This will fall as rain below 1800 meters pretty much everywhere, but it will come down as wet snow between 1800 and 2200 meters and above 2200 meters as dry snow. The biggest questions at the moment are:

  1. How fast and when will the temperatures go up after the snowfall from Thursday and Friday?
  2. Can we expect more snowfall during and after the weekend?

The snowpack will get thinner rapidly below 2000 meters, because of the rain on the south side of the Alps (and later in the western Alps) and the Föhn storm in the northern Alps. The next update will be published on Friday. There are a lot of uncertainties, so with these updates you can make a better decision if you want to travel to the Alps to ride some powder this weekend. If you are traveling to the Alps the next couple of days and you want to support wePowder and this forecast, book your accommodation using this link. We receive a small percentage of every booking made through this link and this helps us a lot to improve wePowder and advice you even better. Thanks in advance! In this forecast:

  • Strong southern current
  • Lots of precipitation
  • Snowline around 1500-1900 meter
  • PowderAdvice: go into the high alpine, but wait with planning after tomorrow's update

Strong southern current

It is not unusual to see strong southerns current during spring that will bring lots of snow around the Monte Rosa, (south of) the Gotthard, the Ortler and the southern Engadin. But it's happening pretty early this year. This southern current will cause the temperature to rise and will bring in lots of moisture from the Mediterranean. That looks a bit like this:

The jetstream is turning south
The jetstream is turning south

A storm depression settles west of the Alps
A storm depression settles west of the Alps

And marks the border between cold air in the west and very warm air in the east
And marks the border between cold air in the west and very warm air in the east

Lots of precipitation

During the journey across the Mediterranean Sea this southern currnet picks up a lot of moist air and it hits the southern side of the Alps. A stormy southern Föhn is created on the north side of the Alps, while on the south side (where the clouds collide) they'll have to deal with heavy precipitation. During their trip to the Alps the clouds are forced to rise and cool down, starting to condensate and it will start raining or snowing. The exact opposite happens on the north side of the Alps. The clouds are dropping and dissolve. In short: heavy precipitation in the south and warm and dry air in the north.

Strong southern Föhn
Strong southern Föhn

Lots of freshies in the south
Lots of freshies in the south

Snowline around 1500-1900 meter

The beauty of this process is that so much energy is created when the clouds hit the Alps, that the local air is much colder than what you would expect on the basis of the temperature in that specific layer of air. This is a local process which we call 'orographic cooling'. The bottom line is that a lot of energy is released thatthe air temperature will go down locally thanks to the intensity of the precipitation and condensation. On the south side you also see that cells with colder air are created, which will cause the snow line to drop locally. The freezing level will be around 1900-2200 meters, but might drop to 1500 meters during the most intense storms.

Cold air south of the Alps
Cold air south of the Alps

But the temperature will rise again when the southern current drops after Friday. Let's hope that the sun will come out and that there won't be that much humidity in the air. In that way the snow will remain fresh on north faces above 2200 meters. Forget about that on southern faces. The radiation of the sun is intense and the snow will warm up fast.

Lowest temperatures in the main alpine ridge
Lowest temperatures in the main alpine ridge

PowderAdvice: go into the high alpine, but wait with planning after tomorrow's update

Because of these uncertainties I simply can't give you a final powder advice, but assume that you're good if you are going to resorts with lots of north-facing slopes and search for powder above 2200 meters. You'll have to think of resorts such as Zermatt, Saas Fee, Cervinia, Andermatt, St. Moritz (Corvatsch and Diavolezza) and Passo Tonale. More details tomorrow, especially since some residual clouds might spoil the weekend.

Stay stoked, Morris

Comments


  • Fluc
    Advanced
    Fluc op 30 March 2016 · 12:44
    Nice report 😀
    @meteomorris, what do you think about Val Bedretto (TI) Switzerland on Friday, good idea?
    *Ride hard, stay easy*
  • meteomorris
    Tourist
    meteomorris op 31 March 2016 · 21:15
    @Fluc123 bad weather for a tour!
    May the powder be with you.
  • Fluc
    Advanced
    Fluc op 1 April 2016 · 13:05
    Yeah we mentioned it 😞
    *Ride hard, stay easy*

Reply

You need to be logged in to post a comment in this topic. Login or create an account.

Upgrade to wepowder Pro

  • Extended 14 day forecast
  • Slope angle and exposition terrain layers
  • Inspirational freeride routes
wePowder Pro