Posted on: 2021-02-23 15:07:03 by davidof

Ski touring avalanche fatalities double in 2020/2021 season

With ski resorts closed, probably for the rest of the season, the press are demanding why are there so many fatal avalanches this year.


FranceTV blames the lack of avalanche control work in the ski resorts. The “Parisien” Newspaper claims there are “twice as many victims as normal” and suggests it is the “explosion in the number of ski tourers” this season as well as “low altitude snow that we haven’t seen for a number of years”. According to avalanche expert Alain Duclos “we’ve never seen anything like it”[1]. In the same article Frédéric Jarry of the ANENA says “if we compare this start of the season with the last 15 years then on average there are double the number of accidents ski touring”. Cécile Coléou of Météo France states that “the accidents we have seen in the Vosges (Haute-Rhin) and Jura (Ain) are much rarer in other years”. She blames the cold weather and lack of rain for not stabilizing the snow-pack.  Captain Olivier Cousin, head of the mountain rescue in Briançon (CRS des Alpes) says that “skiers who are unaware of the dangers”. Avalanche expert Manuel Genswein (talking about the Swiss figures) echos this sentiment and points out the amount of ski touring gear sold this winter and the influx beginners. On the other hand guide, Erik Decamp highlights that “it is not just beginners who’ve been caught out”.


All of the above has played a role but as ever the details have been filtered through the press into eye-catching headlines including our own. We’ll try to drill down into the facts, as far as they are known, first up the weather and its affect on the snow.


Weather and Snow-pack


After early season snow, at the end of September, which enabled some lucky locals to ski tour the season started relatively late with the first big falls occurring at the beginning of December with regular snow fall throughout December and January accompanied by cold weather. February saw more snow at valley level but also high altitude rain to 2300 meters and a general stabilization of the snow-pack due to purges or freeze/thaw below that level. There have also been two episodes of Saharan wind blown sand to complicate the situation with a number of purges on the first of these layers.


The autumn was characterized by a thin snow pack at altitude accompanied by an anticyclone - sunny days and cold clear nights. A situation that worried avalanche experts as these are ideal conditions for the formation of a fragile layer of depth hoar crystals. In mid November forecaster Frederic Cabot from Meteo France, Savoie sounded the alarm about a Persistent Weak Layer (PWL) that was developing[2]. Avalanche bulletins noted this problem. Alain Duclos warned of generalized instabilities in the snow-pack and the risk of very large avalanches.


Avalanche, St Christophe en Oisans (credit: CRS des Alpes)


The Avalanche Incidents


It is estimated there are 10 avalanches involving injuries and outside intervention[3] for every fatality but not all skier triggered avalanches get reported. So we’ll examine just the fatal avalanches, which gives us an accurate year on year comparison, to see if there are any key points.


The first avalanche fatality was on the 22nd December 2020 in the Hautes-Alpes near the Col du Lauteret when a guided group triggered a slide that buried a lone skier following in their tracks. A member of the guided group was also injured.


There was a lull until the 12th January when a lone Italian ski instructor, local to the area, was killed in Courchevel. On the 16th a skier, part of a group of two, was buried under 2 to 3 meters of snow in the Vallon de la Sache at Tignes. On the 17th two local nordic skiers were killed on the road above St Christophe en Oisans. On the same day two skiers were caught by an avalanche in a steep couloir in the Vosges. One equipped with an airbag survived, partially buried but with serious injuries the second had no beacon and it took a day for the rescue services to locate his body.


On the 20th a couple were ski touring in the Jura when the husband, on exiting the woods, was buried by a remotely triggered avalanche under 150cm of snow. They had forgotten their avalanche beacons and the burial depth and delay (90 minutes) to recover the victim proved fatal. On the same day a local skier, touring alone was buried on a popular but avalanche prone ski touring route in the Chartreuse mountains, his body was found the following day by a rescue dog. Another lone skier was killed on the 21st the Bauges. He was located the next day using his avalanche beacon.


On the 24th two brothers were caught by an avalanche in the Bauges. Young Breton MTB Champion Ronan Chedaleux was killed by the slide. The slope they were on is known to be avalanche prone by the locals. On the same day a ski Instructor was killed by an avalanche while touring with two colleagues at Arc 2000. He was buried under 3 meters of snow. He was wearing a beacon.


On the 25th a lone ski tourer was killed near the Col du Lauteret. After an extensive search operation he was located using his avalanche beacon the following day. Two “experienced” ski tourers were avalanched on a closed black piste in the Combe des Balmes above the ski resort of Aussois. The victim was wearing an avalanche beacon. The slope is avalanche prone and is controlled when the resort is open.


The following day a ski tourer, part of a group of two, was killed on the Croix de Cassini near l'Alpe d'Huez. The victim was located using his avalanche beacon but was buried under 3 meters of snow. In the Pyrenees at Luz Ardiden another fatality invoving a lone ski tourer. He was located by eye witnesses using the signal from his beacon.

 

On the last day of January a ski tourer from Grenoble was killed on the Pic Blanc du Galibier, near the col du Lauteret by a large avalanche that carried him 400 meters down-slope. He was touring with a friend. Eye witnesses located the victim using his avalanche beacon.


The only non-ski touring fatality occurred on the 5th February. An ice climber was hit by a natural slide in the Hautes-Alpes. Head of the Coudon section of the French Alpine Club (CAF). At the time of the incident there was a thaw with the zero iso at 2700m.


On the 13th Anne Revilliod, a staff member of “la Chamoniarde” (The Chamonix Mountain Rescue and Prevention Association) was killed after falling 50 meters over cliffs in the Combe de Barmerousse after being knocked off her feet by a tiny slab.


On the 15th a lone “steep” skier was killed in the Couloir de Chamoissière under the sumit of the Tabor mountain. His body was located under 30cm of snow using his beacon.


And finally on the 21st a local ski tourer was killed on a closed ski run at les Deux Alpes. His friend was able to locate him after 15 minutes buried under 60 to 80cm of hard debris.


We’ll look at this data in more depth but note that we don’t have a 100% complete picture of the incidents so any conclusions will be fairly broad.


Are the number of avalanches unusual?


To date there have been 20 deaths in 19 incidents. We’ve come out of a couple seasons of relatively benign conditions, a stable snow-pack for most of the season so comparatively this season’s figures look bad but they are not unprecedented. Over the last decade in 2010/11 there were 29 deaths in 19 incidents, 2012/13 36 deaths in 27 incidents, 2014/15 45 deaths in 29 incidents, 2017/18 37 deaths in 26 incidents. The season is not over but it seems like these kinds of conditions are typical every 3 to 4 years.


In an average season there would have been around 13 fatal incidents to date so the figure is significantly higher than normal. On average the type of activity is evenly split between ski touring (9.2 fatal incidents average) and off piste skiing (8.9 average). With the lifts shut to all but strictly controlled club groups there is little off piste skiing this season. Fréd Jarry's claim of a doubling in the number of ski touring incidents is borne out by the statistics. January, with 14 incidents, is nearly 3x the average of 5.5 incidents. So far February with 4 incidents is below the average of 5.1 as was December, 1 incident instead of 2.7. The better figures over the holiday periods may be due to lower visitor numbers in resorts and the lack of off piste skiing. The January figure appears to be mainly weather related.


A number of off piste skiers will have switched to ski touring this season, demand for touring gear, both new and old, has been high. Given that ski touring is estimated to be 3 times more dangerous than off piste skiing it doesn’t need a huge switch to dramatically increase the figures.


Cécile Coléou commented about the cold and incidents in unusual mountain ranges. The snow-pack below 2000 meters is generally stabilized by periods of high altitude rain. When conditions get sketchy skiers often head for the mid-mountain ranges: Vosges, Jura, Bauges, Chartreuse in search of safer conditions but these mid mountain ranges have accounted for 5 fatal incidents this season. If we examine the geographical location of the avalanches by department (average in brackets): Haute Savoie 1 (4.5), Savoie 6 (7.1), Isere 5 (2.3), Hautes-Alpes 4 (3.2), Ain 1, Haute-Rhin 1, Pyrenees 1; there is a more widespread geographical distribution of fatal incidents this season. Fewer in the Savoie departments because the big ski areas have been shut but an increase in the Isere near the major population center of Grenoble.


Experience


Two ski instructors have been killed in incidents and a guided group triggered a slide that killed a skier below. In general groups led by professionals have been less prominent in the statistic this season. At least 9 of the incidents involved experienced back country travelers and nearly all the victims were local to the mountains. Avalanche beacons were used to locate victims in 16 of the incidents. The local nature of victims can be explained by the Covid restrictions which have made holidaying and traveling less attractive. Non-local skiers tend to use professionals which may account for why fewer led groups have featured in the statistics.


Lone Rangers


8 of the incidents involved solo skiers. This is much higher than usual. There is usually a significant delay in reporting someone missing and the rescue operations are long and complex as the exact route is not known to relatives (search for car, overflight of ski touring routes looking for avalanche debris, search of avalanche debris with beacons, dogs, probe lines). It may be that the widespread risk in the mountains this season has surprised these skiers. In general solo skiers favour what is normally less dangerous terrain, a gamble that didn't pay off in January 2021.


Avalanche Size


In four of the incidents burial depth was a decisive factor. This reflects comments by Alain Duclos about the size of observed avalanches this season and is linked to the deeply buried weak layer. At least five of the incidents were on what are known to be avalanche prone slopes. Of course there is no way of knowing if the victims were aware of this or had consulted the avalanche bulletin before travel. In the case of the St Christophe avalanche (Oisans) the two victims had discussed the avalanche control work the day before their trip and may have believed the route was safe.


Resort Avalanches


At least two of the avalanches were on what are normal resort runs. Another was on a resort itinerary. Two other avalanches were within resort boundaries on what may be avalanche controlled slopes in normal seasons. Clearly there is more resort “speed” touring this season.


Summary


It seems the principal issue this year has been a fragile snow-pack over a wide geographical area which has resulted in some large avalanches in unusual locations. Skiers heading for the relative safety of mid mountain ranges have been caught out. This is a heuristic trap. The overall figures are not atypical for this kind of avalanche situation. The fact that ski touring incidents predominate is normal in a year where ski lifts are closed and skiers are seeking out other means to access the mountains. Ski touring, with its long, exposed climbs, increases the risks to back-country travelers. The resort incidents highlight that ski areas are also at risk but given the number of people, especially new skiers, who are touring on closed pistes it doesn’t appear that either of these are decisive factors. Avalanche beacons were used to locate victims in 84% of incidents, the average figure is 85% for ski touring, this is another indication that the victims were generally correctly equipped and not poorly equipped alpine skiers (average 55% for off piste incidents) trying a bit of touring.


The number of solo skiers that have been killed should give cause for reflection. Even a minor incident can be serious if there is no-one to raise the alarm but again the big increase appears to be snow-pack related and lack of appreciation of the conditions.


References


The author is a level 3 French Mountaineering Federation avalanche instructor.


[1] Deux fois plus de victimes d’avalanches : pourquoi la montagne est si dangereuse cette année, Élie Julien (avec Victor Alexandre). Le 26 janvier 2021 Le Parisien.

[2] Savoie Avalanche Forecaster Warns of Persistent Weak Layer Problem and Danger! Persisten Weak Layers at Altitude

[3] Avalanche Poodles

[4] Old Snow, Persistent Weak Layers and Guided Groups


Further Information

Incident Reports

Early Season Snowpacks

https://www.anena.org/

http://www.data-avalanche.org/

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