Mont Blanc three metres shorter than in 2010 - and 16 more peak facts

Researchers say the height of the mountain changes continuously, but this year’s measurement is the most accurate yet. We explore more on the ‘white mountain’

30 September 2021

The summit of the mountain made up of around 15 metres of snow and ice Pic: pedrosala / Shutterstock

By Joanna York and Hannah Thompson

Mont Blanc has lost three metres in height since 2010, researchers report, after measurements from September 2021 show it is now 4,807.81 metres tall.

The mountain, which is the tallest in Europe, was measured by land surveyors during a three-day mission, which has taken place every two years since 2001.

During the mission, experts used satellite sensors to model the ice cap that sits at the top of the mountain. 

This enables them to “create a precise and reliable data bank to be used by experts and passed onto future generations,” two experts from this year’s mission said in a press conference.

Mountain height ‘changes continuously'

The latest measurement is very close to the ‘official’ height of the mountain, which is known as 4,809m.

This measure dates back to the end of the 19th century but, in reality, the height of the mountain changes continuously, the experts said.

The highest recorded height was in 2010, at 4,810.9 metres, and was close to the first measurement, which was made in 2001 (4,810.4 metres).

In contrast, the 2019 measurement (4,806.03 metres) was so “exceptionally low” that it was not made public, with researchers preferring to wait for the 2021 figures for “more scientific explanations”.

On average the height of the mountain has decreased by 13 centimetres per year since 2001, due to changes in the ice and snow at the top.

Meanwhile the summit of the actual rocky peak is at 4,792 metres and increases by up to three millimetres per year due to shifting tectonic plates.

Why does the height change?

The height fluctuates due to the fact that the summit is made up of around 15 metres of snow and ice, the exact height of which changes in volume according to the weather

Some years, heavy precipitation and weak winds mean that more snow accumulates at the top, making the summit taller.

As such, the mountain is at its tallest at the end of summer while in winter, stronger winds clear more snow reducing the overall height.

Land surveyor Jean des Garets told France 3 that tthe researchers “removed the most recent snowfall at the summit, going down about 40 or 50 centimetres [to] measure the highest point of the ice below” when making their calculations.

He said that the 2021 figure had reached a “level of precision never seen until now”, as good weather conditions on the day of the expedition meant that researchers could stay at the summit for three hours.

Experts said that the impact of climate change on the mountain was difficult to measure, and warned against “making hasty conclusions based on data that only goes back to 2001”.

16 facts about the ‘white mountain’

  1. Mont Blanc is ‘owned’ by both France and Italy, as it is spread over the Franco-Italian border. It is known as Monte Bianco in Italy.
  2. Mont Blanc's summit is in France, but its ‘Italian summit’ is called Monte Bianco di Courmayeur. At 4,748m, it is considered to be Italy’s highest point.
  3. The record for the youngest person to climb Mont Blanc was set in 2009 by British 10-year-old Asher Silver.
  4. An 11km-long tunnel links Chamonix, France, and Courmayeur, Italy. Its route goes directly underneath the mountain.
  5. Chamonix is the town located at the foot of Mont Blanc. It held the first Winter Olympic Games in 1924.
  6. The lowest recorded temperature on Mont Blanc is -43°C, set in January 1893.
  7. Jacques Balmat and Michel-Gabriel Paccard, a hunter and physician respectively, were the first to climb Mont Blanc, reaching the summit on August 8, 1786.
  8. Marie Paradis, a servant living in Chamonix, became the first woman to reach the summit of Mont Blanc. She climbed with Jacques Balmat.
  9. Spaniard Kilian Jornet Burgada currently holds the Mont Blanc speed record on foot. He ascended and descended from Chamonix in just four hours, 57 minutes, and 34 seconds, on July 11, 2013.
  10. More than 20,000 climbers reach the summit of the mountain every year, and as many as 30,000 attempt it.
  11. Summiting the mountain is a goal for many mountaineers, but less experienced walkers can also walk and hike in the foothills of the mountain and the Chamonix region.
  12. Two passenger aircraft have crashed into the mountain. Both were Air India flights. The first crashed in 1950, and the second in 1966. The flights killed 160 people in total. The cause of the first is a mystery, but the second is thought to have been caused by miscommunication on board, leading to wrong information on the position of the mountain relative to the aircraft.
  13. Sadly, there are deaths on the mountain every year, with more than 8,000 climbers having died in total.
  14. The mountain is home to many sporting events each year, including the gruelling Ultra Trail du Mont Blanc ultra-marathon, which is a 170km race along the area’s mountain tracks
  15. American climber Scott Putnam is the most recent high-profile mountaineer to go missing on the mountain. Rescuers called off the search for the father-of-three more than a week after he went missing, saying “if he is still on the mountain, it is almost certain that he is dead”.
  16. France has introduced new measures in a bid to protect the mountain, with local authorities repeatedly campaigning for more awareness of how excess numbers of visitors and climbers are allegedly damaging the peak. 

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