Powderalert#23 is ON as of Wednesday

By meteomorris on 5 March 2013 · 0

Image: [Pulverdude](http://wepowder.nl/forum/topic/71360)
Image: [Pulverdude](http://wepowder.nl/forum/topic/71360)

A very active low pressure area is moving via the Pyrenees to the Gulf of Genua on Tuesday. It will cause a big southern stau that will last for 48 hours. You can notice that already on Tuesday. There’s a warning for heavy winds in the northern Alps in Switzerland and Austria, a result of the rising southern föhn.

::Genua-low:: in development
::Genua-low:: in development

The temperature in the northern Alps will even rise to a higher level, and the freezing level will be around a whopping 2400 meters. The snow will melt even harder in the valleys that are sensitive for föhnwinds. You’ll see the meadows in the valleys come out in some places.

Snow in the south

It’s quite a paradox, but when there’s a snow-killing southern föhn in the northern Alps, there’s a southern stau in the southern Alps, bringing lots of fresh powder! You can experience a southern stau in pretty much every mountain range in the world, but it can be really strong in the Alps. This is because the shape of the Alps and the proximity of a lot of water (called the Mediterranean). The main alpine ridge is perpendicular to all the fronts coming from the south. And because the mountains rise about 2500 meters in just a few kilometers, the clouds are forced to climb rapidly, resulting in a lot of precipitation.

Extra influenced by the sea

This process is getting even better because of the proximity of the Mediterrenean. The water is relatively warm, and as a result the colder air is bringing extra moisture and that intensifies the precipitation. It’s like the lake-effect they have in Utah, only ten times stronger. You shouldn’t be surprised when it snows up to 150 centimeters in 24-48 hours.

The stau left of the ridge, the föhn on the right

Snowline will drop to 1000 meters

The snowline will drop to 1000 meters in the Pelvoux and the Italian Piemonte on Tuesday night and Wednesday morning. It will rise again to 1400-1600 on Wednesday afternoon and Thursday and the freezing level will be around 1800-2000 meters. I expect around 50-70 centimeter of freshies above 2000 meters between Tuesday evening and Thursday evening. The snow will be pretty wet between 1300 and 1900 meters.

A real southern stau

Powder advice

  • Wednesday: treeruns in the French southern Alps and the Italian Piemonte. The snow is getting heavier during the day.

  • Thursday: snow for the complete southern Alps. You can find the most snow (50-90 centimeters) in the western and southern Piemonte. The sun will come out in the morning in that region and that means: bluebird and powder! It’s still snowing in the southern Alps central and the southern Alps east. You can expect around 20-50 centimeters of freshies.

  • Friday: The weather is changing, with some sun, some snow and some rain in the western and southern Alps. The snowline will be around 1700-2000 meters and this just won’t be the best day of the week. It’s not really good in the northern Alps as well, because the föhn basically killed all the snow.

Western stau on Saturday and Sunday

A new front will pass the Alps on Saturday and Sunday. The first snow will fall in the southwest, but the wind will be gone in the night from Saturday to Sunday and it will start snowing in the French northern Alps and the rest of the northern Alps as well. The snowline will be pretty high at first (1500-1700 meters), but will drop to 1200 meters later. Sunday morning can be really good in the French Alps. The front has already passed and you can enjoy some freshies above 1800 meters with some sunshine.

Winter in the week of 10-17 March?

Earlier I wrote ‘Colder temperatures will be back after the 10th of March and chances for significant snow for the northern Alps will increase’. And this could still happen. The temperature will drop after March 11th (let’s say around 15 degrees colder), and we’ll definitely see some snow in the north stau regions of the northern Alps. More details later this week, but winter is just like Schwarzenegger this season. ‘I’ll be back!’.

If you have any questions about where to go and the forecast, do not hesitate to drop me a question!

Stay stoked



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