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Avalanche accidents in summer

If you want to be safe in the mountains, you must be aware of the avalanche danger in steep, snow-covered terrain. This doesn't just apply in winter, avalanches can occur in summer too, especially after significant snowfall. They may be much less common than in winter, but they claim on average one to two lives in Switzerland each year. "Some climbers are completely unaware of this hazard," explains SLF avalanche forecaster Frank Techel. To date, there has also been little research done into avalanche accidents in summer.

With this in mind, Techel and three doctors from Lausanne University Hospital carried out a study examining all fatal avalanche accidents in open terrain in Switzerland between 1984 and 2014. Of the 482 recorded accidents, 21 (4%) took place in the summer months between June and October, resulting in 40 fatalities. 

Lawinenunfall Zinalrothorn

This wet slab avalanche (outlined in red) swept away two climbers as they were descending the Zinalrothorn on June 19, 2014. They plunged several hundred metres down a rock face and were dead when rescuers arrived. (Photo: B. Jelk).

Severe injuries from falling

Thirty-eight of the 40 victims were on high-altitude backcountry tours when they were hit by avalanches in exposed terrain, causing them to fall several hundred metres. Severe fall-related injuries were therefore the main cause of death – unlike in winter, when most victims die from asphyxiation as a result of being completely buried in the avalanche. This scenario was less common with summer avalanches.

While avalanche accidents are much rarer in summer, the average number of fatalities per avalanche was somewhat higher than in winter in the cases examined. According to the study's authors, the main reason for this is that groups on high-altitude tours are usually roped together. "If the avalanche hits one person, it often takes the whole rope team down with it," says Techel. Rescue, whether by fellow climbers or professional rescue teams, is difficult in the case of summer avalanches, since they tend to occur in steep, inaccessible terrain.

Dealing with avalanche danger in summer

To avoid getting into trouble, please bear in mind the following:

  • Take avalanche danger into account when planning the route. The SLF also issues avalanche bulletins in summer when major snowfall has occurred.
  • The main hazards in summer are freshly fallen and drifted snow and wet-snow avalanches. Avalanche prone locations are assessed the same way as in winter.
  • Even small snowslides can have fatal consequences, especially when there is a risk of falling. This should be taken into consideration when selecting a route.


Avalanches in the summer



Frank Techel