Off Piste Snow Report – N French Alps – 11th December 2022
Brrrrrrr!! It is cold. But the powder is light. However, the snow depths are still not so much and there is a risk of hitting rocks. We have reports of some injuries due to contact with rocks and a park and fly.
There is also some instability. The snowpack is not settled and there is still little skier compaction. Some of us are sticking with slopes lower than 30 degrees. If you go on steeper slopes be sure you think it will not release. The danger rating is 3 which means there is a considerable risk of triggering an avalanche on a slope steeper than 30 degrees. This could be because you are underneath it or on it.
In the meantime. Sunday was a great day. Light powder and perfect sunshine. So there could be a few more of these days in the next 2 weeks. This will be interspersed with cloudy snowy days. Keep tracking the weather.
Snow depths have now improved in the N French Alps following several episodes of snowfall last week. Around 20 to 30 cm of fresh snow over 3 days has helped to top up the previously thin snowpack, with more expected in the week ahead.
Here’s the Meteo France image of off-piste snow depths for the Haute Tarentaise on 10th December 2022.
There are some lovely light powder snow conditions above 2000 m, very pleasant to ski. However, we’re taking it cautiously as there is a weak layer in the snowpack, which formed after a series of very cold clear nights on a very thin snowpack.
We’ve just received reports of an avalanche fatality which happened yesterday in the Var area of the S French Alps. And Meteo-France put out this warning for the Southern French Alps yesterday, Saturday: “There is a “high risk of avalanche triggering by skiers” and recommended “the greatest caution (…) for the practice of mountain activities off marked and open slopes” on the Hautes-Alpes and Ubaye massifs and Oisans”. The Southern French Alps have received a lot more snowfall than us in the North, so this sad avalanche accident is a precursor for us. In fact there were 3 deaths in avalanches this week, two in the Southern French Alps and one in the Northern French Alps.
Don’t rule out piste-skiing on these higher slopes with a few cm of fresh snow on top of the safer groomed snow. Lovely!
Despite the fresh snow, there are still plenty of rocks around, and hollows that have not yet been filled up with snow. Heavily dug-out banked mountain-bike tracks are a particular hazard, causing some nasty drop-offs and dangerous landings for off-piste skiers, until snow fills the tracks!
Below 2000 m, where the snow has been humidified by milder temperatures/rain on Friday, and then refrozen, the snow surface is very crusted and tricky to ski.
Recent natural avalanche activity. Wayne Watson photo
Pictures from people having fun in the off-piste today
Avalanche Bulletin 11th December 2022
Current danger rating in Haute Tarentaise
The bulletin reports a considerable danger rating of 3 above 2100m, and a moderate risk of 2 below, on slopes facing all directions.
Problem 1: A persistent weak layer, particularly on N facing slopes above 2100 m. The recent 20/30 cm of fresh snow has fallen on top of a weak layer/s. This risk seems less present below 2100 m, thanks to a short mild spell on Friday, which helped to humidify those fragile layers, followed by refreezing on Sunday (an extremely cold day) which will ‘solidify’ the humidified snow and limit the risk.
Problem 2: New areas of windslab snow will be forming during the day on Sunday, as N winds transport the snow, causing drifting. Areas along the French/Italian border, like Val d’Isere, which have received significant amounts of fresh snow over the weekend, will be particularly affected by this. We may well see some spontaneous slab releases, and slabs can also be released by a skier passing by, or even distance triggered by a skier.
Weather forecast 12th to 16th December (and indication beyond)
MONDAY, DECEMBER 12
Very cold in the morning, sunny then covered at the end of the day
In the mountains and in the valleys good weather. It is still very cold in the morning, then high clouds arrive from the south during the afternoon. Veiled sky at the end of the day and the following night with some possible flakes in the second part of the night. After very cold minimum temperatures, the maximums still do not climb much with 1 to 3 degrees in the plain as well as in low valleys, -6/-8 in station. (isothermal 0 degrees around 800m) Weak wind from West to North.
TUESDAY, DECEMBER 13
Risk of snow at low altitude
The Savoie will be under a disturbed west-southwest flow with low-altitude snow initially going up in the middle mountains on the Pre-Alps (1700m) but can drag for a long time at lower altitude in inland valleys. Improvement at the end of the day before a new milder disturbed passage the following night. Cumulation of 20cm on average at 1800m but all this remains very uncertain given the instability of the models at the moment.
West dominant wind at altitude (50/60 km/h).
Temperatures rising significantly with still generalized frosts in the morning with -2/-3 in the plain and -5 in the interior valleys under 1000m, they rise around 4 to 5 degrees in the afternoon in the plain as well as in the lower valleys and around zero at 1800m in the station.
WEDNESDAY, DECEMBER 14
always disturbed but much less cold
The disturbed flow remains in our region with blocked weather and precipitation. Rain and snow limit around 1600m. Cumulation expected Thursday morning from 5 in Maurienne to 20 cm in Beaufortain in 24 hours above 1800m. Temperatures continue to rise, from 3 to 10 degrees in the plain and from 0 to 7 degrees to 1000 m isothermal 0 degrees pointing to 2000 m all day long.
THURSDAY: Covered
The sky often remains overcast with very cloudy with rare rainfall on the border massifs of the Maurienne and the Thabor/Galilbier sector. Temperatures are falling with again generalized frosts in the morning and no more than 3 to 4 degrees in the afternoon. Locally unpleasant northeast wind.
FRIDAY: Improvement
Return of some beautiful clearings especially in the mountains. Temperatures are slowly rising again while remaining cold for the season.
Zero degree isothermal around 1500m.SATURDAY, DECEMBER 17, SUNDAY, DECEMBER 18
SATURDAY: Beautiful
Good weather planned for next weekend with temperatures rising above seasonal normals.
SUNDAY: Beautiful
Another beautiful day on Sunday with a marked softness in the mountains with a zero-degree isothermal that climbs to 3000m.
MONDAY, DECEMBER 19 and TUESDAY, DECEMBER 20
Will new disturbances arrive in time to drop (snow) packages at the feet of the fir trees? For the moment calm and soft Monday then a disturbance will pass on Tuesday 20. It’s very uncertain given the deadline but it’s good to believe it a little more!
Tip of the Week
Be CAREFUL of the early season snowpack, not only because it’s still thin, but because it is very unstable. The early season snowpack is a very fragile snowpack on most aspects, and VERY VERY fragile on shaded and north-facing slopes. It regularly catches out even the most experienced of us.
Even before the significant snowfalls that we’ve received in the last few days, there has been noticeable natural avalanche activity, with slabs ‘popping out’. See Wayne Watson’s photo higher up in this blog. These naturally occurring events are a clue as to how especially sensitive the snowpack currently is to triggering.
Be on your guard, and stick to the less steep slopes (less than 30°) away from terrain traps unless you really know what you’re doing.
The post Off Piste Snow Report – N French Alps – 11th December 2022 appeared first on Henry's Avalanche Talk.