Between 100 and 340 cm of fresh snow in the high alpine!


By meteomorris on 25 November 2016 · 0

It's snowing heavily in the northwest of Italy, the east of the French Alps and the south of Switzerland. Wednesday was the day where the most snow came down. The temperatures were quite high, with a snow line between 1600 and 2200 meters. In this forecast:

  • Amazing amounts of fresh snow
  • Emergency situations in the Italian Piedmont
  • Avalanche danger HIGH to EXTREME
  • Less snow came down further west
  • PowderAdvice for the weekend
  • Long term

Amazing amounts of fresh snow

The snow in the southwest of the Alps came down in three dumps since Friday. This locally resulted in bizarre amounts of fresh snow. The measuring stations report that the snow cover grew between 100 cm and 190 cm. The amounts of fresh snow that came down are even higher. The snow settles because of the wind, the temperature and the weight of the snow itself. To illustrate this: about 250 cm of fresh snow came down around the Simplon since Tuesday, but the snow cover grew 'only' with 107 cm. The high temperatures and the weight of the fresh snow settled the snow cover.

Over 250 cm of fresh snow around the Simplon
Over 250 cm of fresh snow around the Simplon

If the snow cover around the Simplon grew with 107 cm thanks to 250 cm of fresh snow, than the question arises how much snow came down in Bonneval sur Arc. The snow cover has grown over there with 145 cm. So how much snow came down? About 3 meters or maybe even 3,5? It's definitely a guesstimate, simply because the measuring stations of Météo France only measure the snow cover and not the amounts of fresh snow that came down. And that's quite a difference.

Bonneval sur Arc + 145 cm
Bonneval sur Arc + 145 cm

Emergency situations in the Italian Piedmont

The amounts of snow that came down in the Italian Piedmont since Tuesday are simply unreal. The snow cover grew with 80 cm to 190 cm and they locally measured 340 cm of fresh snow. Of course the snow pack settled over here as well. The snow cover in Sestrière grew with 150 cm since yesterday (Thursday) and it's still snowing.

Sestrière, snow cover +150 cm
Sestrière, snow cover +150 cm

The precipitation came down as snow above 2300 meters, but it rained below that altitude. And so much water came down. Rivers flooded and locally the infrastructure was destroyed. Check it out on Twitter using the hashtag #allertameteoPIE.

450 mm of rain in just 36 hours

This was the highest amount of precipitation that I found. It was measured on the Colle del Vaccera. 450 mm of rain was measured at 1450 meter altitue in just 36 hours. Just imagine it was a bit colder. It might have brought 450 cm of snow.

450 mm of rain in just 36 hours
450 mm of rain in just 36 hours

Avalanche danger HIGH to EXTREME

These huge amounts of snow cause problems. The first major avalanches have been observed in the typical avalanche gullies, sometimes reaching far into the valley. The avalanche danger is HIGH or EXTREME in all mountain areas in the western and northern Piedmont, but also in the eastern parts of the Aosta, the area around the Swiss Simplon and the border regions between France and Italy (Haute Tarentaise, Haute Maurienne and Queyras). Authorities therefore call to postpone ski touring at least to Saturday and check out how the conditions are again on Saturday morning. The temperatures were high, huge amounts of snow came down, the temperature will rise again on Saturday and huge spontaneous avalanches are possible the next 36 hours.

Avalanches in the Piedmont
Avalanches in the Piedmont

Less snow came down further west

The most snow came down (and is still coming down, because it's still snowing in the Piedmont) in the Italian Piedmont and the border areas with Italy and France. More west the snow amounts that came down rapidly decrease. Thus, Val d'Isère is still loaded with fresh snow, but Tignes received less snow and even less snow came down in La Plagne.

Val d'Isère
Val d'Isère

Tignes
Tignes

La Plagne
La Plagne

You can check out these differences between east (Val d'Isère) and west (La Plagne) on our local snow maps of the here (click and scroll down).

Our snow map of the last 6 days can give you a good impression how much snow came down. Three things you have to keep in mind:

  1. The snow that came down on the north side of the main alpine ride and in the far west of the Alps (from last Saturday) is pretty much gone below 2000 meters.
  2. The snow line is between 1700 and 2200 meters now.
  3. Much more snow came down in the red areas on the snow map than the map indicates.

Snowfall the last 6 days
Snowfall the last 6 days

Zoom in on an area (like Val Thorens) and the differences are striking. Some fresh snow came down in Val Thorens, but that's nothing compared to the areas near the Italian border, where it really has been dumping above 2200 meters altitude.

Snowfall the last 6 days in the Vanoise/Haute Maurienne
Snowfall the last 6 days in the Vanoise/Haute Maurienne

PowderAdvice for the weekend

It will stop snowing today (Friday). There aren't that much lifts open in the northwest of Italy and the east of France and you should go to very high altitude. Some lifts will open in the Monte Rosa area (Alagna-Gressoney) on Saturday. This opening was actually scheduled for Friday, but it's postponed because of the heavy snowfall. You could also go to Cervinia-Zermatt, but keep in mind that less snow came down on the Swiss side of the border and the snow is more influenced by the wind. The same goes for Saas Fee, with less fresh snow and lots of wind. The lifts are running in Montgenèvre. It's still dumping like crazy and the lifts are running on Saturday.

My bet would still be Gressoney or Montgenèvre on Saturday. You could go out on a tour on Sunday. Start on a high altitude mountain pass. But check out the avalanche forecast first!!!

Long term

A cold front from the north will hit the Alps on Sunday. This causes a small northern Stau. This could bring 10-15 cm of snow to the northwest of Switzerland and northern Vorarlberg. The rest of the northern Alps will get 2-5 cm.

northern Stau
northern Stau

A high-pressure area will position itself over the Alps after Sunday. This will result in a significant drop of temperature, but this high pressure area will also keep the storms at distance. According to the latest calculations, the high pressure area is pretty persistent, so we don't have to expect much fresh snow until the middle of next week. There's still some moisture in the air in the Po Valley and that could be the biggest suprise in combination with the current from the east and some cold air. There's room for new storms in the beginning of December.

High pressure area is settling
High pressure area is settling

Stay stoked. Morris


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