Case Study - Avalanche in Val d'Isere

Photo looking down over the debris field - Image Credit www.data-avalanche.org

This is a case study of an avalanche that took place on the 11th of December 2018 in the area of Val d'Isere in the French Alps. All persons involved survived. 

On the morning of December 11th, a group of 3 skiers took a route into an area known as the Banane on the Bellevarde face. (altitude 1800-2700m). Conditions were clear with no wind and excellent visibility. All 3 skiers had transceivers, shovels, and probes, plus the lead skier also had an avalanche airbag. They knew the previous weather and current avalanche rating. There was no obvious signs of avalanche activity in the area.

The days stats are as follows:

Avalanche Rating: 3/5

Avalanche Problem: Buried weak layer above 2400m between 40cm and 70cm down in the snow pack and wind slab/storm slab.

Avalanche Trigger: Small loading - 1 skier.

Slope Aspect: North facing

Avalanche Size: 2

Hazards: Multiple terrain traps and cliff bands. Several convex roles and potential release points. 

Below is the survivor account:

"On Tuesday 11th of December 2018 I was skiing off piste with two friends in the Bellevarde area of Val D'isere.
I was wearing an airbag and had a beeper shovel and probe on me. My friends did not have airbags but had everything else.

The problem on the day was a weak layer above 2400 meters that had been identified by Henry Scheinwind of Henrys Avalanche Talk, which I knew about. The previous 3 days had seen stormy weather with sleet and rain below 2400 meters which bonded the layers together. Above this level it just resulted in a weak layer. I had had one preparatory run down the Face (on piste and some off piste just near the piste) on my own then joined my friends. We decided to go off piste and follow the many tracks we saw over to the Banane area thinking this would be an indication of safety. It wasn't!!

This would have been 10.40 am. The weather was blue bird and no wind. My friends were about 3 meters behind me when I decided to head down.

I did one turn and the whole lot went! Half a meter deep and a split line about 60 meters across! I tried to ski out, but it was just too big."

Image showing the debris field below the slab release. Many other ski tracks are visible. - Image credit www.data-avalanche.org

"I jettisoned my sticks and got down into the fetal position and pulled the handle on my ABS bag. Then the snow was all around me and over my head. I think I went off a lip and corkscrewed in the air as I landed badly and ruptured my left knee. My skis came off at this point.

Then It was like being inside a washing machine with blue and white snow flushing around me as I tumbled over and over. I have been told it went for 500 meters. I came to a standstill with my mouth just in the air being able to breath. The rest of my body was completely submerged except for one hand and a foot. Within two minutes someone was digging me out and within 15 minutes the piste rescue services were there and blood-waggoned me off the mountain. I would recommend everyone who goes off piste to buy an airbag without exception. It saved my life! 
My friends missed being swept away by a mere 3 meters. The outcome could have been very different had they been caught in it, as they had no airbags."

Image showing crown line and avalanche path over cliff bands.- Image credit www.ledauphine.com/

We asked the skiers if there was anything they would do differently, or any advice they would give to people looking to ski off piste in this area. This is their response:

"I've learnt to always observe what the experts say. Never be lulled into a false sense of security by tracks already laid down.

To have a more serious attitude about the mountain and not take too many risks. I would say to other skiers going off piste in this area

to be wary of the Santons gully on the far right. If it goes into there it will pile up deep and crush you. Always go with the right equipment 

and people who know how to ski off piste and can effect a proper search and rescue."

In Summary: 

The avalanche was triggered by minimal loading and slid on a buried weak layer. The avalanche danger rating was considerable (3/5). The forecast warned of the problem and the elevations & aspects affected. Although the skiers knew the above information the presence of tracks and absence of any visible avalanche activity convinced them that the slope was stable.

What can we learn: 

1: Having the appropriate equipment and training is essential.

2: Tracks don't guarantee safety.

3: Ride with others who have the appropriate training. 

4: Be aware of terrain features that pose a hazard if the slope does release. Cliff bands and hollows can dramatically change your chances of survival in the event of an avalanche. 

We are really grateful to the skiers involved for sharing their experience with us so that we can hopefully help others learn from it and learn more about the risks involved in back country and off piste skiing & snowboarding. 

For more information on avalanche kit and forecasts check out our blog post here 
This particular avalanche is also mentioned on this page with Henry's Avalanche Talks 
For more information on avalanche safety Ortovox have this page: Ortovox Safety Lab

And for more avalanche information check out the following links:
Avalanche Canada  
Henry's Avalanche Talks