Mont Blanc: how can we reduce accidents in the Goûter couloir?

From 1990 to 2017, French mountain police force registers show 347 rescue operations in the Goûter couloir, on the normal route on Mont Blanc, which resulted in 102 deaths and 230 injuries. Presenting a strong objective danger, the Goûter couloir tarnishes the image of mountaineering. There is no real reason why this high number of accidents cannot be reduced. The Petzl Foundation wishes to raise awareness and instigate discussions to find solutions. We have launched some studies which we hope will provide clear messages about the inherent dangers of the normal route. 

SEPTEMBER 2014  •  Updated in June 2020

ID card

  • Project partner: Project initiated and led by the Petzl Foundation
  • Country: France
  • Project type: Accident prevention
  • Budget: Funding studies (accident, falling rocks and solutions), Petzl Foundation involvement, for a total of € 180,000 since 2009
  • Studies: Accidentology, Stone-fall and Suggested solutions (in French)

Download accidentology studies

A new study on rockfalls in the Couloir du Goûter: valuable information for mountaineers!

When and why do rocks fall in the Couloir du Goûter, on the normal route up Mont Blanc? Which periods are the most dangerous for mountaineers? What is the ideal time of day to cross the couloir and climb the Goûter ridge?
A study conducted using seismic sensors has been published to improve our knowledge of the causes of rock destabilisation. It also offers valuable information for anyone preparing to climb Mont Blanc, by reducing the risks they will face.

The Philippe Descamps conference on accidentology of the normal route up Mont Blanc

Sustainable Summits Conference, June 2018, Chamonix.
Start: 4 min 10
Questions & Answers: 55 min

The hazards of the normal route

The Petzl Foundation is committed to reviewing modes of access to the Mont Blanc, one of the most attractive peaks in the world. Visited by around 35,000 mountaineers every year, access and safety issuesare particularly important in the Goûter couloir, on the normal route from Saint Gervais, which is very exposed to falling rocks.

Rockfall in the Couloir du Goûter

Located between the Tête-Rousse refuge (3,167 m) and the Goûter refuge (3,835 m), this couloir has long been recognized as dangerous. The high exposure of this passage was confirmed by two studies commissioned by the Petzl Foundation (Accidentology and Stone-fall studies, English summary). 

Sometimes called the "death couloir", it is particularly difficult in high summer, as it is swept by frequent rockfalls. However, most of the summit contenders, expert mountaineers or not, must go through this couloir, which isunavoidable on the normal route.

Goûter couloir

It is important to clearly separate the issue of a route’s difficultyfrom thatcaused by its dangers. The Petzl Foundation’s contribution does not intend to makeaccess easier on this route, but to limit exposure to the objective dangers that lead to so many serious accidents.

The Goûter couloir

A number of safety improvements have already been made. Information is available from weather reports, guidebooks and brochures, as well as supervision by mountain guides and effective rescue services. Equipment has been installed in the Goûter couloir, such as a cable to help those crossing it. Tracking tags have also been installed on the Goûter dome.

The Petzl Foundation wishes to contribute to improving safety conditions in this key passage. A technical study was conducted by the MEIGE company, along with a team of geotechnical experts. This study is based on accidents, the increased number of mountaineers attempting the summit, climate change, site topography, rock falls, etc. 

Solutions to objective dangers have been suggested which necessitate the installation of light mountain equipment, on the part of the couloir which is most exposed. Various projects have been considered and studied. Among the suggested solutions, is a narrow tunnel which isconsidered to be fully viable and appropriate.

Study n°1 : Accidentology of the Goûter couloir

Accidentology of the Goûter couloir

The mountain police force of the Haute-Savoie and Petzl Foundation’s collaborative study aims to better understand the hazards of stone fall encountered during the normal route of Mont Blanc, from the refuge of Tête Rousse to the Goûter refuge.

Crossing the Goûter couloir in September 2013.
Crossing the Goûter couloir in September 2013.

From 1990 to 2011, the police force registers show 291 persons rescued during 256 incidents, which resulted with 74 deaths and 180 injuries. Despite strong annual variations, the number of casualties seems to be stable in the long term (more than 3 dead and 8 injured on average per year). There is a slight increase during the last decade if we refer to the frequentation of the two refuges located on the route. 

The exact location of the incidents is not very precise in one rescue out of five (18%). 38% of  casualties were located within the first hundred metres of the first crossing of the Goûter couloir and 28% in the 550 metre long ridge directly beneath the former Goûter refuge. We can estimate that about half of the accidents were located in the couloir.

The detailed study of the casualties’ and witness statements can explain some circumstances more precisely. Falls appear as the first cause (49%) of the incidents, before stone fall (30%) but lots of falls are the clear consequence of, but not recorded as, stone falls.


Casualties are mostly male (81%), middle-aged (39 years old average), of varied origin (27 countries represented, and first of all, those neighbouring Mont Blanc), and the majority were unroped. Incidents happened mainly around midday and more regularly during descent. Amateurs were the most exposed; but we find clients (11%) and some professionals also amongst the statistics.

Although there are many variables to consider, the study of these incidents in the last two decades establishes particular objective danger within the Goûter couloir, especially during the crossing. It’s a true “black spot”. It also highlights the need to consider the overall itinerary, including the ridge between the crossing of the couloir and the Aiguille du Goûter.

Jacques Mourey’s poster (EDYTEM, Chambéry) « Mountaineers exposed to rockfalls in the Grand Couloir du Goûter (normal route of mont-Blanc). A monitoring system for a better assessment of their vulnerability. »

Follow-up and analysis of stone falls

In the summer of 2011, the geotechnical engineering company Alpes Ingé realised a statistic study concerning stone fall and the frequentation of the Goûter couloir, which is the main access to Mont Blanc. Observations indicate thataround a thousand mountaineers were faced with falling stones, on an estimated 17,000 crossings. Factors which aggravate or reduce risk have also been identified. Better informed mountaineers can manage risks better.


This statistical study followed on from the safety study conducted by the MEIGE engineering team in February 2011 which investigated the stone fall hazards in the couloir and also examined the objective dangers of the site. The Alpes Ingé team observation took place from Monday June 20th to Sunday September 18th 2011.

Stone fall study

During this period, the engineers spent 42 days in the field, however, during this whole study 754 “stone fall” events were recorded of which 251 consisted of a single rock during the event (33%), 140 with 4 rocks at a time (19%) and 363 events with more than 5 rocks (48%). 75% of stone falls arrived between 10am and 4.30pm. Hours which are the most critical are between 11am and 1.30 pm, equating to 34% of the events observed. But stone fall remains an important hazard all day.

During the most critical hours, between 11am and 11.30am, we can observe that a stone fall occurs on average every 17 minutes.

The snow cover within the couloir didn’t have any noticeable effect concerning stone fall but there is a direct influence on the number of rocks which fell in the same event and on the height of the stones’ rebound.We notice a huge reduction of stone falls when the temperature is negative. The correlation is not so clear when the temperature is positive, as a high positive temperature isn’t synonymous with stone falls.

We notice also that stone falls are more regular when the humidity is less than 50%. Low humidity is synonymous with clear weather and with thaws linked to solar radiation, meaning that stone falls are more likely when the weather is good. On the contrary, stone falls reduce when the weather is more humid.

Goûter couloir - winter Goûter couloir - summer
The appearance of the Goûter couloir may change depending on weather conditions. It’s more prone to falling rocks during dry summers (right).

Number of crossings

During the observation period, the Alpes Ingé team recorded :

• 5928 mountaineers crossing the couloir, of which 2,537 were ascending (43%) and 3,391 descending (57%).

•  The team estimated the total number of crossings to be between 17,000 to 17,500 throughout the summer period – 7,300 to 7,500 ascending and between 9,700 and 10,000 descending.

•  The number of visitors to the site is lowest before 8.30am.

•  76% of the crossings are between 9am and 3pm and 40% between 11.30am and 2pm.

During peak crossing hours, between 12.30am and 1pm, one person crosses the couloir every 105 seconds.

The Alpes Ingé team observed mountaineers in perilous situations, in the couloir whilst stone falls were occurring. They recorded 363 mountaineers in difficulty due to rock fall. This represented 6% of the total number of crossings with 15% to 40% occurring on the 5 most dangerous days.

During the observation period in the 2011 season, one thousand mountaineers were confronted by stone fall while they were crossing the couloir.
During peak crossing hours, between 12.30am and 1pm, one mountaineer every 21 minutes could find themselves in a perilous situation.

Goûter couloir in dry conditions
In dry conditions, rock fall is more common in the Goûter couloir.

Our study is based on a partial observation of a statistical analysis conducted over 42 days in the field. Any published results must be considered cautiously. The study does, however, give an unquestionable level of seriousness to both stone fall and also to the number of mountaineers exposed whilst crossing the Goûter couloir.


The regularity and size of the stone falls observed confirm the existence of an objective danger when crossing the couloir. Stones fall may occur any time during the season, but we can observe strong variations linked directly with the climatic condition.

Periods less exposed to stone fall are the coldest during the season, with negative temperatures and overcast skies.

The periods which are most exposed to stone fall are the sunniest when temperatures are high and humidity is low. Generally, these periods attract the highest number of mountaineers crossing the Goûter couloir, ascending or descending from the summit of Mont Blanc.

Study n°2 : Analysis of falling rocks and numbers of ascents during summer 2011

Picto PDF To download this report in french, clik here.

How to reduce accidents in the Goûter couloir

There is no easy solution to the dangers of the Goûter couloir. Priority should be given to information and prevention. But we cannot exclude other means of reducing risk, such as a totally new route, building shelters or a tunnel on the couloir.

Schema To instigate real discussion, the Petzl Foundation has studied several solutions suggested by different experts.

The idea of a tunnel, suggested by the Saint-Gervais guides, would provide lasting protection without visibly altering the mountain and having a limited impact on the environment. However it would require significant work and this suggestion is still being debated.

Making this route safer will not in any way make it easier technically-speaking. Also, the candidates to the summit should know that this ascension requires physical and mental strength . The entire normal route, not just the couloir itself, should be taken into account when exploring potential solutions.

Picto PDF Download the suggested solutions (in French) [Format pdf - 4.47Mo]

Reaching the top of Mont Blanc, A concern for climbers

In the summer of 2012, the French Mountain Coordination and the Petzl Foundation launched an information campaign aimed at candidates of the “roof of the Alps”. Practical advice and information is given in ten languages.

In May 2014, the Chamoniarde association and the Mountain Coordination, with the support of the Petzl Foundation, launched the website  which extends this information campaign.

Download the brochure in your language:


For the Petzl Foundation, this information campaign backs up the studies accidentology, stone-fall and suggested solutions, which aim to give climbers a better understanding of the dangers of the normal route 

The campaign :

Opinions and forums

By funding non-profit projects, the Petzl Foundation works for the common good of our mountain communities. To reduce the risk in the Goûter couloir, we wish to

  • Provide objective matter for discussion.
  • Promote awareness.
  • Encourage calculated risk as opposed to "Russian roulette".
  • Reduce risk without defacing the mountain.
  • Find real solutions.
  • Channel energies and build consensus.

Our commitment is also reflected in our press coverage and at conferences.

Picto PDF Read Paul Petzl’s point of view on page 28 « Rencontres citoyennes de la montagne 2012 ».
Picto PDF Paul Petzl talks about the Goûter couloir in the magazine « Montagnes du monde 2013 ».
Picto PDF. The Petzl Foundation in the magazine « Montagnes du monde 2014 ».

Updated in june 2020



Since 2012, the Petzl Foundation has funded research into mountain sport accidents. Our long-term aim is to improve prevention. (...)

Find out more -  Our safety projects