Off Piste Snow Report – N French Alps – 20th March 2023

by | Mar 20, 2023 | Avalanche Accident, Avalanche Safety, Off Piste, Snow Reports, Weather Forecast

Is it safe? It depends on you (‘safe’ if you apply the prevention points here: https://henrysavalanchetalk.com/off-piste-quick-reference/ )

Last week saw plenty of avalanche activity in the Northern French Alps, many of them triggered by skiers. We’ve also heard of 3 people sadly being killed by avalanches in Savoie over the last 7 days. More about this lower down in our report.

Following substantial snowfall over the last couple of weeks, off-piste snow depths at 2000 m and above are now around average to good for the time of season. Below that altitude, they’re lower than normal, and virtually non-existant below 1500 m, even on the colder North facing slopes.

Image above shows Meteo France off-piste snow depths for the Haute Tarentaise area of Savoie on 18th March

There’s been a series of avalanches in the Northern French Alps, many involving off-piste skiers and ski tourers, who triggered the avalanches themselves (almost all avalanche accidents are triggered by the victims, someone in their group… or, on the increase, are avalanches triggered by people above onto victims below).

During avalanche prevention work to secure the pistes, remarkable amounts of snow  have been dislodged by explosives, and a ‘piste basher’ was even taken for a ride by an avalanche while working at the Col de Bellvard in La Toussuire ski resort near St Jean de Maurienne. 

Stéphane Bornet, Director of ANENA (the French Avalanche Association) attributes this high amount of avalanche activity to the very different types of weather conditions this winter. For about 6 weeks (end of January and all of February) saw no snowfall. A series of very cold clear nights over this period helped form a persistent weak layer of ‘sugar snow’, particularly on cold N’ish facing slopes above 2200 m. Then March arrived, bringing large amounts of snow at high altitude, landing on top of this weak layer, and blown into big accumulations by the wind.

Urging off-piste skiers to be extremely careful, Bornet explained “The new snow fell heavily, with a lot of wind, on an unconsolidated surface layer that was made up of the ‘sugary’ angular grains (also referred to by professionals in English as  : ‘faceted grains’ or simply ‘facets’… more in the past, but some still  call ‘depth hoar’), not allowing this new snow to bond with this older snow layer”.  (Translation taken from report by France Bleu – see link in paragraph below).

One of the many avalanche accidents happened this past Friday in the Col du Palet area near Tignes. It happened on a NW facing slope at around 2700 m altitude in a  ‘considerable’ 3 out of 5 avalanche danger rating above 2200 m, and involved 4 ski tourers skiing in a group of 5. Three of them were buried to different degrees, one of whom, under 4 m of snow, very sadly died. It was a very large avalanche that they triggered,  300 m wide by 400 m long. Account (in French) of the accident here. 

Avalanche Bulletin

The current avalanche danger is a “considerable” 3 out of 5 on the colder N’ish facing slopes above 2200 m (note the black coloring on the ‘clover’ symbol representing slope aspect just to the left (O = West). These are the sort of slopes where the the persistent weak layer(s) of unconsolidated snow developed, particularly during the cold clear nights. The instability is tenacious and will continue to be with us for weeks to come – thus the official term ‘persistent weak layer’. See Data Avalanche’s snow stability test below done on 17th March, for a demonstration of the weak layer.  

Weather forecast 20th to 27th March

MONDAY 20th March: After Sundays scatterings of snow above 1800 m, Monday will quickly clear up to a sunny day. Light N wind. 0° C at 1800 m, rising to 2600 m.

TUESDAY 21st March: A calm and sunny start to the day, with thin high cloud.  0°C at 2900 m. Light NW wind.

WEDNESDAY 22nd March: Calm, sunny and mild for the time of season.

THURSDAY 23rd & FRIDAY 24th March: Becoming cloudy, with precipitation – possibly considerable  snowfall above 2100/2300 m, rain lower.

SATURDAY 25th: Mixture of cloud and bright spells. 

SUNDAY 26th onwards: Unsettled with precipitation (snow/rain)

Below is Meteo Blue’s weather chart for Val d’Isere for the next fortnight.

Tip of the Week

Avoid skiing above ‘Terrain Traps’.
As part of the extreme caution advised in areas where the persistent weak layer instability exists (see above), pay extra attention to ‘Terrain Traps’
Over the years I’ve noticed that many of the worst avalanche accidents involve ‘Terrain Traps’.
These are any terrain feature that makes the consequences of being taken in an avalanche worse.  Even a very small avalanche can be deadly if it takes you
  • over a cliff
  • into a tree
  • into a hole (and buries you)
  • into a pond or lake (or even a river or stream)
In many seasons, more than half of all deadly ski accidents involve ‘Terrain Traps’ as the, or one of the, primary reasons for the serious injury or death of the victim. So if we all avoided steep slopes above ‘Terrain Traps’ (especially just after snow storms), we could probably reduce avalanche deaths by close to half.
This simple tip was the inspiration for these thoughts expressed in my short informal video piece here, posted last summer,  “Avalanche Safety in 15 Minutes”. (It’s actually only around 13 mins long and contains some great images and Avalanche video clips).

“Safety is freedom”