The danger of climbing Mont Blanc seen by science | The Mountaineer | Sports

Last summer, Antoine Rattin had a broken arm in a sling and a nasty injury to his face, near the temple. Everyone was wondering what had happened to the keeper of the Goûter refuge, an almost obligatory stopover on the way to the summit of Mont Blanc (4,808 meters), and no one missed his answer: “It was in the Grand Corridor… “. In reality, he was born again. Mountain guides and most Spanish climbers know this place as “the bowling”, a horizontal pass only 100 meters long which constitutes one of the black spots of the massif. Crossing this corridor means exposing yourself to a slightly exasperating game in which you must prevent the rocks rolling down the slope from dragging you down or killing you. Hit by a medium boulder, Antoine Rattin was thrown about fifteen meters down the slope but managed to stop. The less fortunate are picked up by the helicopter a few hundred meters further and taken to the morgue. Between June 15 and September 15, in peak season, an average of 21,350 people have crossed this point since 2017, representing an annual average of 3.7 fatal accidents. Antoine Rattin passes through this fateful place several times each summer, as do many high mountain guides, who shortcut their clients and spend a few seconds moving from one secure area to another. These are the tensest seconds of the entire day, a tension that will be repeated on the return from the summit.

All of this data comes from a study by Savoie Mont Blanc University which makes it possible for the first time not only to prepare an analysis of the risks assumed by mountaineers on the two most popular routes, but also to quantify them. In the mountains, there are two main types of dangers: objective and subjective. The latter have their trigger in the actions and decisions of the mountaineers, as well as in all the errors (logistics, knowledge, physical preparation, overestimation of their abilities, bad equipment, etc.) that they can make. Objective dangers refer to the terrain and, although it is possible to avoid their impact to a certain extent, it is a risk to be assumed when practicing any type of activity in the mountains: rockfalls, avalanches snow, storms, lightning, cracks in glaciers. …In an unprecedented way, French researchers have clarified in the most precise way possible a key question: what exactly are we talking about when we talk about objective dangers on the normal routes of Mont Blanc?

The most popular route to the summit of Mont Blanc is the Voie Royale, which passes by the Goûter refuge. The second, called Trois Monts, crosses the slopes of Mont Blanc du Tacul and Mont Maudit before reaching the roof of the Alps. The objective dangers that await climbers on the two routes are of a very different nature. Thermal conditions directly influence the frequency and quantity of rockfall due to Bowling alley while they in no way affect the fall of the seracs (masses of ice) which threaten those who cross the north-northwest slope of Mont Blanc de Tacul. In the latter scenario, the seracs can fall at any time, whereas in the Bowling alley Less dangerous time slots can be identified: between 2 a.m. and 12 p.m., there are the fewest rockfalls, and especially between 9 a.m. and 10 a.m. Activity increases later, and is critical between 6 p.m. and 7 p.m. This information is crucial to enable climbers to reduce their exposure to risks. This is not the case on the north-northwest slope of the Tacul, where it is very difficult to anticipate the fall of a serac and only a careful reading of the terrain would allow the discovery of very fractured or small ice falls could provide clues for choosing which route to follow.

On the Tacul slopes, the average number of fatal accidents per year is 0.6, and the risk is twice as high as on the Voie Royale. However, those who aspire to reach the roof of Europe spend much more time exposed to the potential danger of the Tacul (some even hours), while on the route that passes through the Goûter, passing through the dangerous Bowling alley It only takes half a minute (for a quick rise). However, it happens that many more mountaineers pass through this last point, where, moreover, the frequency of rockfalls is much greater. The scientists who carried out the study emphasize the Bowling alley as the most dangerous point in the Alps and, surely, on the planet.

To know the frequency of rockfalls at this point, a seismic device and sensor were installed in 2019 which recorded the influx of climbers. Between 2016 and 2020, cameras recorded all the Tacul serac falls as well as climber traffic. In the case of Bowling alley A telling fact was recorded: a large landslide occurred every 37 minutes, and its magnitude increased towards the end of the summer season. The scientists who prepared the work point out that there is a classification of risks: those that society tolerates are defined as “acceptable risks” and it is not worth investing in reducing them. On the other hand, the “tolerable risk” is that with which society can live and benefit from it while trying to reduce its threat (driving a car, or practicing mountaineering, for example). The danger of Bowling alley It is three times higher than the road mortality rate in France, which means that an average mountaineer is as likely to die in a single action as if they normally drive their car for three years. However, for a 45-year-old Frenchman, in Bowling alley would mean a probability of dying ten times lower than their normal probability of dying. On the other hand, if a 15 year old child passed through the Bowling alley would double your chances of dying, as much as a professional mountaineer or a 45-year-old mountain guide who passes the same place ten times a year.

Scientists point out that the conditions and the dangerousness of the two scenarios on Mont Blanc will deteriorate in the future: the permafrost (permanently frozen layer of soil) on the west face of the Aiguille du Goûter weakens each year and its degradation will accelerate. Warming of the Tacul ice could accelerate its cracking and the fall of ice masses. And then we will have to revisit the reality of its objective dangers.

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