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The idea of a mountain growing may sound strange, but that is exactly what happens. Its height can even change in just a few years, as has occurred with Mont Blanc which, according to measurements released in France on Wednesday, now reaches 4,807.47 metres above sea level, almost two metres more than in 2023.
The new calculations were carried out on 17 September by experts from the Haute-Savoie Departmental Chamber of Surveyors, whose territory includes part of the mountain shared by France and Italy.
The results were officially presented on Wednesday in Saint-Gervais-Mont-Blanc, on the French side of the massif, showing an increase of 1.88 metres in three years, reversing the trend of previous years, when the summit had been lower.
Presenting the results, the president of the Chamber of Surveyors, Jean des Garets, recalled that "the summit is in constant motion".
Why Mont Blanc's altitude changes over time
The apparent "growth" is not due to movements of the mountain itself but to variations in the snow and ice cap that covers the top.
The height of Europe's second-highest peak changes according to the accumulation and redistribution of snow, influenced by wind, precipitation, temperature, sunshine and seasonal weather conditions.
For this reason, the periodic measurement campaigns produce different results. Between 2000 and 2010 the height was repeatedly measured at around 4,810 metres. Afterwards, a gradual decrease was recorded.
In 2021 Mont Blanc reached 4,807.81 metres, while in 2023 it dropped to 4,805.59 metres, the lowest figure in recent years. The 2026 measurement, by contrast, puts the mountain back above 4,807 metres.
The Alps' highest peak rises back above 4,807 metres
The new survey confirms that Mont Blanc remains a summit in constant evolution. Compared with the historic figure from 1894, its current altitude is around 27 centimetres higher.
For experts, the succession of measurements is also a useful tool for monitoring the effects of weather and climate conditions on the Alpine environment.