SLF’s Swiss Long-Term Statistics of Avalanche Victims

SLF’s Swiss Long-Term Statistics of Avalanche Victims. The SLF, (Institute for Snow and Avalanche Research) has been collecting data on all the avalanche accidents that happened in Switzerland since the winter 1936/37. This is an overview of their statistics:

Avalanche victims since 1936

The annual average number of fatalities over the entire period is 25 (Fig. 1).

Figure 1:Avalanche fatalities in Switzerland since 1936/37. The graph illustrates the fall in the number of fatalities in buildings and on transportation routes. The black line shows the 20-years mean values. Its maximal value is 31 and its actual value 23. The long-year mean value since 1936/37 (81 years) is 25. SLF’s Swiss Long-Term Statistics of Avalanche Victims.
Figure 1:Avalanche fatalities in Switzerland since 1936/37. The graph illustrates the fall in the number of fatalities in buildings and on transportation routes. The black line shows the 20-years mean values. Its maximal value is 31 and its actual value 23. The long-year mean value since 1936/37 (81 years) is 25. SLF’s Swiss Long-Term Statistics of Avalanche Victims.

Spatial distribution of fatal accidents during the last twenty years

 More than 90% of the fatal avalanche accidents during the last twenty years occurred in uncontrolled terrain, like for example during off-piste skiing and snowboarding or during backcountry touring on ski or snowshoes. As can be seen in Figure 2, a particularly large number of accidents occurred in the cantons of Valais and Grisons.

Fig. 2: Regional distribution of the fatal avalanche accidents in Switzerland (20 years). For each of the more than 120 subregions, which are the basis for the regionalization of the avalanche bulletin, the number of fatal accidents was counted. The larger a symbol, the more accidents occurred in this region. SLF’s Swiss Long-Term Statistics of Avalanche Victims .
Fig. 2: Regional distribution of the fatal avalanche accidents in Switzerland (20 years). For each of the more than 120 subregions, which are the basis for the regionalization of the avalanche bulletin, the number of fatal accidents was counted. The larger a symbol, the more accidents occurred in this region. SLF’s Swiss Long-Term Statistics of Avalanche Victims .

But what is the reason of this clustering?

Is the clustering of accidents a consequence of a high touring frequency in these regions, or are there other reasons for a higher avalanche accident risk in these regions?

As there is no data of how many number of people goes off-piste or touring in skis/boards or snowshoeing in the backcountry, SLF investigated two portals – www.bergportal.ch and www.camptocamp.org

They looked at the date and the location for which a report was posted. There were 15,000 geo-referenced reports during the five winters 2009/10 to 2013/14 (see map below, Fig. 3). Looks like a large number, but it is only a small proportion of the actual backcountry users and  as they say, it …’may have an unknown bias leading to potentially misleading conclusions. Therefore, we compared the usage pattern with a survey concerning the Swiss avalanche bulletin (conducted in 2014). This comparison showed that the posted backcountry condition reports provide a plausible picture of regional backcountry usage. However, we would like to emphasise to be careful when interpreting this regional distribution.’

were posted for this region. geodata©swisstopo. SLF’s Swiss Long-Term Statistics of Avalanche Victims.
Fig 3. Regional distribution of the location of www.bergportal.ch and www.camptocamp.org conditions reports (5 winters, 2009/10-
2012/13). As in Fig. 2, for each of the more than 120 sub-regions the number reports was counted. The larger a symbol, the more reports
were posted for this region. geodata©swisstopo. SLF’s Swiss Long-Term Statistics of Avalanche Victims.

The reports show that the average backcountry usage per surface area is higher in the North and in the Valais than in Grisons or the South

During the five winters from 2009/10 to 2013/14, the number of severe avalanche accidents on backcountry tours was twice as high in Valais and Grisons (per surface area or per reported backcountry activity), compared to the North. The avalanche accidents that were considered as severe are those where at least one person was injured, fully buried or finished dead.

They also looked for other explanations, such as the snowpack structure: The more inner-alpine areas in Valais and Grisons are not only those with a frequently shallow snowpack, but usually they have an unfavourable snowpack structure. This means that the snowpack base is weak or that prominent weak snow layers are located within the snowpack. (See Fig 4).

Fig. 4: This map shows regional patterns of snowpack structure ranging from the most unfavorable with an often more pronounced old snow problem (dark grey areas) to those with an often better snowpack structure (light grey areas). The regional ranking is based on feedback from mountain guides (old snow problem), snow-profiles and Rutschblock tests from our observer network for the five winters 2009/10 to 2013/14. SLF’s Swiss Long-Term Statistics of Avalanche Victims.
Fig. 4: This map shows regional patterns of snowpack structure ranging from the most unfavorable with an often more pronounced old
snow problem (dark grey areas) to those with an often better snowpack structure (light grey areas). The regional ranking is based on
feedback from mountain guides (old snow problem), snow-profiles and Rutschblock tests from our observer network for the five winters
2009/10 to 2013/14. SLF’s Swiss Long-Term Statistics of Avalanche Victims.

Looking at avalanche accidents statistics one can see that weak layers have been the failure of numerous fatal avalanche accidents . These kinds of persistent weak layers remain unstable for a longer time than new snow weakness. Also, even experienced people have difficulty in detecting these dangerous slopes, as the weakness is buried deep in the snowpack and can sometimes only be found by digging a snow-profile.

Where to find information about an old snow problem?

Aside of digging a snow-profile yourself, you can find information through avalanche bulletins (danger description, snowpack and weather section), and the snow stability map, showing the most recent snow-profiles.

The avalanche bulletin not only informs about the danger level, the most dangerous slope aspects and elevations, but also the most relevant avalanche pattern. As an example, if persistent weak layers within the snow are considered of concern, then an ‘old snow’ pattern is given. If considered important, even more details concerning the avalanche problem can be found in the danger description, as shown in this avalanche bulletin from January 2014 that specified:

“Old Snow

Danger Description

Distinct weak layers exist in the bottom section of the snowpack in particular on shady slopes. Avalanches can be released by a single winter sport participant. They can penetrate down to the ground and reach a dangerous size. Whumpfing sounds and the formation of shooting cracks when stepping on the snowpack can indicate the danger. The conditions are precarious for snow sport activities outside marked and open pistes. Defensive route selection is required.

The SLF recommendations are:

“Less touring activity, but more avalanche accidents mean a higher risk of being involved in a severe avalanche accident in the inner-alpine regions, like in Valais or Grisons. As avalanches triggered in the old snow are usually dangerously large, a defensive behaviour is appropriate. In addition, the damage potential in case of an avalanche can be limited by maintaining spacing between individuals and descending very steep slopes one person at a time.”

Avalanche accidents are life-threatening events! – further report from SLF

According to statistics, only a little more than one in two people who are completely buried by an avalanche (head in the snow) survive. The most common cause of death among those who are completely buried is asphyxiation because the person often has no air supply or has access to only a small pocket of air. The chances of a person surviving a complete burial therefore reduce significantly after just 15 minutes (Fig. 3, for details refer to Procter et al., 2016). For this reason, companions have a crucial role to play in quickly locating and freeing the person who is buried.

Fig 5. Survival curve showing the proportion of victims surviving complete burial in open terrain (backcountry, off-piste) from 2005/06 until 2012/13. During this period the probability of a person surviving complete burial stood at a little more than 50%. All persons who were completely buried and did not die from trauma injuries were considered.SLF’s Swiss Long-Term Statistics of Avalanche Victims.
Fig 5. Survival curve showing the proportion of victims surviving complete burial in open terrain (backcountry, off-piste) from 2005/06 until 2012/13. During this period the probability of a person surviving complete burial stood at a little more than 50%. All persons who were completely buried and did not die from trauma injuries were considered.SLF’s Swiss Long-Term Statistics of Avalanche Victims.

Avalanche accidents per danger level

According to long-term average figures, most fatal accidents occur when danger level 3 (considerable) applies (Fig. 6).

Figure 6: Fatal avalanche accidents per danger level for persons caught while engaging in backcountry or off-piste activities, or in buildings or on transportation routes (accidents between 1998/99 and 2017/18). SLF’s Swiss Long-Term Statistics of Avalanche Victims.
Figure 6: Fatal avalanche accidents per danger level for persons caught while engaging in backcountry or off-piste activities, or in buildings or on transportation routes (accidents between 1998/99 and 2017/18). SLF’s Swiss Long-Term Statistics of Avalanche Victims.

You may want to read the interview we made last year to Coco Torres, former Head of Operations at Valle de Las Leñas on how to control avalanches in this high -prone avalanche area.

We have already covered many news due to this latest spat of snow storms in Europe, as the hotel that was hit by an avalanche of 300 meters of width in Eastern Switzerland. And two ski patrollers got killed setting avalanche control charges in the French resort of Morillon in the Grand Massif.

Recently a British skier was killed after suffering a cardiac arrest on a chairlift falling 32 feet to the ground in Méribel resort in Les Trois Vallées. You can see our recent article on how avalanches claimed two lives in Switzerland the past week. And read more what is the real risk of avalanchesThree Germans have been killed by an avalanche near Lech and a fourth is missing.

The-Ski-Guru TRAVEL can organise your bespoke ski trip to the Americas, Alps or Japan, including for those going from Britain to Europe, booking your Eurotunnel trip, and for all trips: lodging, lift tickets, rentals, ski school, and all you need for an excellent vacation. Go to https://www.the-ski-guru.com/travel and upload your information – this page will be updated soon with more travel ideas. Check our Easter offer to Obergurgl-Hochgurgl and Sölden to ski with your family.

You can start thinking about your trip, by reading the articles on the Planning your Ski Trip tab.  Or how to pack for your family ski trip.  If taking your furry friend abroad to the continent, read about the new Pet Travel Scheme update from DEFRA. Check out our tips for driving to the mountains.  If flying and renting a car in Europe, beware of the extra charges they will pass to you if you want winter tyres, snow chains or ski racks. If driving, check the winter tyres news for Europe and North America.

Cleaning a railway in Hochfilzen- Austrian Tyrol. Photo: Kerstin Joensson-AP. SLF’s Swiss Long-Term Statistics of Avalanche Victims.
Cleaning a railway in Hochfilzen- Austrian Tyrol. Photo: Kerstin Joensson-AP. SLF’s Swiss Long-Term Statistics of Avalanche Victims.

Or you can read our last news on equipment as seen at the London Ski Show. Also, the new range of skis of Black Crows, one of our favourite brands. Lots of snow makes you wonder how the resorts deal with the avalanche danger. Here you can read the interview to Coco Torres, former Head of Operations of Las Leñas, in Argentina, as how they dealt with avalanches at the resort. 

Or perhaps you may choose to read the Ski Resort NewsSki Passes News, and the Must-Read Guides to Lech,  Zermatt,  CourmayeurVal di Fiemme and Crans-Montana. Coming soon will be the guide to St Anton. Or  watch an amazing heli flight over the Mont Blanc Massif. Also see tips on how not to be scammed when booking a ski chalet.

You can also read what’s new at Les Trois Vallées and the last article on what is new at the Tirol ski areas,  in Cervinia, in La Plagne, in 3 Zinnen Dolomites ,  in Adelboden, Lenk and Kandertal, in Gstaad, in Chamonix,  in Georgia’s Gudauri Resort and in the Skicircus Saalbach Hinterglemm Leogang Fieberbrunn. And how the US Ski Team has chosen Alpe Cimbra to train for the following four ski seasons as their European home.  Here is the link to our post on the My Voucher Codes ranking of best European Ski Resorts.  

Crested Butte will have a new chairlift to replace Teocalli lift for the 2019/20 ski season.

You can plan where to eat in Aspen Snowmass or which events to attend on-mountain while there.  Sudtirol ski areas have started and their famous Christmas markets have kicked off too. And Cortina D’Ampezzo is getting ready for this winter and the 2021 World Ski Championships.  

Another classic resort, such as St Moritz has been in the news for its famous Cresta Run be opened again for women after a 89 years ban.

Also, you can read how Grandvalira will be staying together as one lift ticket company and how they are adding Ordino Arcalis to  this offer. And also read how someone tried to sabotage some lifts in Vallnord’s Pal Arinsal. And as if it is starting to be a trend, there were two lifts sabotaged in Passo Rolle, in Val di Fiemme, Trentino. Fortunately they were repaired in record time to open to the public.  Also, Mt Hood Meadows was forced to evacuate one lift with 150 skiers and boarders due to a power failure. And the same was the case in a lift with 140 skiers/boarders in Whitefish, Montana.  Or read about the latest investments in Whistler Blackcomb. Or see how Taos is going against the industry trend, and instead of merging with the two biggest oligopolies in skiing at the moment, it goes and buys an airline to get more bums in resort. Or how Jackson Hole is appealing to families and beginners – it is not only a resort for expert skiers anymore. Another great area for families is Stubaital in the Tirol. And a new coming ski area that got funding for its first lift is Skeetawk in Alaska.  Courmayeur is opening this season two new trails, one that is 70% steep – not for the faint-hearted! Or read how a group of experienced industry insiders got together to purchase Tamarack Resort. And how Peak Resorts finalised the acquisition of the resorts of Snow Time. You can also check how Vermont’s ski passes are the most expensive in New England. And talking about Vermont, you can read on how Killington is planning to change its North Ridge triple chair with a fixed-gripped quad.

Avalanche over the Neptuno piste in Las Leñas. SLF’s Swiss Long-Term Statistics of Avalanche Victims.
Avalanche over the Neptuno piste in Las Leñas. SLF’s Swiss Long-Term Statistics of Avalanche Victims.

Also read how one employee of Aspen Ski Co got caught in an avalanche but got out unscathed while scouting terrain for the Aspen Mountain Powder Tours. Or how the a gondola of the new American Eagle lift from Copper Mountain crashed into the snow in a trial run. The resort confirmed that the chondola will be fixed before it’s opening day. Plus this week, some gondolas got tangled in Hochzillertal. And there was a gas explosion at the Grand Hotel Zermatterhof that injured six, before its opening date.

You can keep up to date on how are the sales for the EPIC and IKON passes are doing here. Read how Emma, the first Digital Mountain Assistant, is launched in Keystone now and will be rolled to eight other resorts this season. And even read about the new incorporation to the IKON Pass: Valle Nevado. Here is also a post on the South American resorts.  

Also, Rob Katz and his wife Elana Amsterdam donated 2 million USD in grants to support mental and behavioural health programs in ski towns of North America. And see how Aspen Skiing Company released its sustainability report 2018. 

And here is a summary of a report by LISTEX on the State of the UK Snowsports Market.

And what Switzerland could look by 2060 due to climate change.

Or check out how now with the EPIC Pass you can ski in Europe, specifically in Les Trois Vallées and the resorts of Skirama Dolomiti in Trentino’s Italy. Or see our review of L’Héliopic Hotel Sweet & Spa if thinking in staying in Chamonix this winter.

Featured Image: An avalanche in the Cenidor trail in Las Leñas, just next to a green trail (Venus). SLF’s Swiss Long-Term Statistics of Avalanche Victims. 

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