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Mont Blanc massif

Mountain range in the Alps

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Aerial photo of Mont Blanc , Massif du Mont-Blanc , Courmayeur , Val Ferret, Aiguille Verte , Mer de Glace and other glaciers.
kallerna · CC BY-SA 4.0

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Through Italy, Switzerland and European Union

The massif forms a watershed between the vast catchments of the rivers Rhône and Po, and a tripoint between France, Italy and Switzerland; it also marks the border between two climate regions by separating the northern and western Alps from the southern Alps. The mountains of the massif consist mostly of granite and gneiss rocks and at high altitudes the vegetation is an arctic-alpine flora.

The valleys that delimit the massif were used as communication routes by the Romans until they left around the 5th century AD. The region remained of some military importance through to the mid-20th century. A peasant farming economy operated within these valleys for many centuries until the glaciers and mountains were "discovered" by the outside world in the 18th century. Word of these impressive sights began to spread, and Mont Blanc was first climbed in 1786, marking the start of the sport of mountaineering. The region is now a major tourist destination, drawing in over six million visitors per year. It provides a wide range of opportunities for outdoor recreation and activities such as sight-seeing, hiking, rock climbing, mountaineering and skiing. Around one hundred people a year die across its mountains and, occasionally, bodies have been lost and entombed in its glaciers for decades.

Access into the mountains is facilitated by cable cars, mountain railways and mountain huts which offer overnight refuge to climbers and skiers. The long-distance Tour du Mont Blanc hiking trail circumnavigates the whole massif in an 11-day trek of 170 kilometres (110 mi). The Mont Blanc Tunnel connects the French town of Chamonix on the northern side with the Italian town of Courmayeur in the south. The high mountains have provided many opportunities for scientific research, including neutrino measurements within the tunnel and impact of climate change on its highest slopes. Recent rises in average temperatures have led to significant glacial retreat across the massif and an awareness of the need for better environmental protection, including a call for World Heritage Site status.

Geography

The Mont Blanc massif is 46 kilometres (29 mi) long and lies in a southwest to northeasterly direction across the borders of France (Haute-Savoie and Savoie), Italy (Aosta Valley) and Switzerland (western Valais). At its widest point the massif is 20 km (12 mi) across. The northwestern side of the massif lies mostly within France, and is bounded by the valley of the Arve, containing the towns of Argentière, Chamonix and Les Houches. To the west it is bounded by the Val Montjoie, containing Les Contamines-Montjoie and the river Le Bon Nant which flows northwards to a confluence with the Arve near Saint-Gervais-les-Bains, and onwards to the Rhône.

The southern side of the massif lies mostly within Italy and is bounded by the Val Veny and Val Ferret whose watercourses meet just above Courmayeur. From Courmayeur these waters flow southwards as the Dora Baltea towards Aosta, eventually joining the Po. However, the extreme western end of the southern side of the massif does lie within France and is bounded by the Vallée des Glaciers (which connects to the Val Veny over the watershed of the col de la Seigne), and its waters flow southwards towards the Isère and onwards to the Rhône.

The northernmost section of the massif falls within Switzerland, and is bounded to the east by a separate valley, confusingly also called Val Ferret, and which separates it from the Pennine Alps. Its watercourse, la Dranse de Ferret, flows northwards to join the Rhône at Martigny. The west side of the northern end of the massif is drained by the Trient, also joining the Rhône near Martigny.

The borders of all three countries converge at a tripoint near the summit of Mont Dolent at an altitude of 3,820 metres (12,533 ft). From here the French – Italian border runs southwestwards along a ridge of high summits on the southern side of the massif, many of which are over 4,000 metres (13,123 ft) in height, including the Grandes Jorasses, Rochefort Ridge, Dent du Géant, Mont Maudit, Mont Blanc and its western satellite, the Aiguille de Bionnassay. From here the border turns southwards over the Dômes de Miage and Aiguille de Tré la Tête before dropping down to the Col de la Seigne. North of Mont Dolent the border between France and Switzerland meanders roughly north-northwestwards along a ridge-line of slightly lower peaks, including the Aiguille d'Argentière, the Aiguille du Chardonnet and the Aiguille du Tour, before dropping down to the Col de Balme. The Swiss – Italian border runs southwest from Mont Dolent, down to the twin passes of Col Ferret.

The massif contains 11 main summits over 4,000 metres (13,123 ft) in altitude, as well as numerous subsidiary points above this height. Crowning the massif is Mont Blanc (4,808 metres (15,774 ft)), the highest mountain in the Alps and in western Europe. From the summit of Mont Blanc to the Arve near Chamonix there is a 3,800 metres (12,500 ft) drop in altitude over a distance of just 8 kilometres (5.0 mi). Because of its great elevation, much of the massif is snow- and ice-covered, and has been deeply dissected by glaciers. The Mer de Glace is the longest glacier in the range as well as the longest in France and the second longest in the Alps. The debris-covered Miage Glacier on the southern side of the massif is the longest in Italy. The summit of Mont Blanc is an ice cap whose thickness varies from year to year.

The entire massif can be circumnavigated by the Tour du Mont Blanc, a walking route of approximately 170 kilometres (110 mi). It usually takes around 11 days to complete, but is also used for an annual mountain ultramarathon, with top competitors expected to complete the whole route in less than 21 hours.

The main mountain passes, or cols, that connect different valleys and towns around the Mont Blanc massif are:

  • Col du Bonhomme 2,329 m (7,641 ft) (path, links Contamines – Beaufort – Les Chapieux)
  • Col de la Seigne 2,516 m (8,255 ft) (path, links Bourg Saint Maurice – Les Chapieux – Courmayeur)
  • Col Ferret 2,490 m (8,169 ft) (path, links Courmayeur – Orsières)
  • Col de Champex 1,497 m (4,911 ft) and La Forclaz, or Fenêtre d'Arpette 2,655 m (8,711 ft) (path and road, links Orsières - Trient Valley)
  • Col de Balme 2,191 m (7,188 ft) (path, links Trient Valley – Chamonix)
  • Col de la Forclaz 1,527 m (5,010 ft) (major road, links Chamonix – Martigny)

Summits

The Mont Blanc massif includes eleven independent and six subsidiary summits over 4,000 metres (13,123 ft) in height. These (including Mont Blanc) are shared between Italy and France only, the highest in Switzerland being the Aiguille d'Argentière. The massif is amongst the three major subranges of the Alps having the highest concentration of four-thousanders, together with the Pennine Alps and the Bernese Alps.

The first ascent of Mont Blanc in 1786 by Jacques Balmat and Michel Paccard initiated the sport of alpine mountaineering, and it was during the golden age of alpinism (1854–65) and the silver age of alpinism (1865–82) that the majority of the main summits of the massif were first attained. Members of the England-based Alpine Club were instrumental in many of the first ascents, usually accompanied by guides from Chamonix or Courmayeur, such as Michel Croz, Michel Payot and Émile Rey, as well as the Swiss guide, Christian Almer. Across the massif there are now more than two thousand different mountaineering routes to the summits, ranging greatly in both length and difficulty. These attract climbers from all over the world who, unlike the early ascensionists, now have access to numerous climbing guidebooks, modern safety equipment, good information on climbing routes and technical difficulty, as well as weather forecasts and mountain accommodation and food.

Glaciers

A wide range of glaciers and glacial structures can be found across the Mont Blanc massif, all of which can be easily reached or viewed. Glaciers cover 170 square kilometres (66 mi2) of the massif, of which 110 km2 (42 mi2) fall within France. The Mer de Glace is the largest glacier in the western Alps, and the second largest in Europe. It has a total length of 12 km (7.5 mi) from highest snowfield to terminus and an area of 35–40 km2 (14–15 sq mi).

At around 10 km (6 mi) in length, the Miage Glacier is Italy's longest glacier and also the largest debris-covered glacier in Europe. Other large glaciers include the Argentière Glacier (9 km (5.6 mi)), the Saleina Glacier (6 km (3.7 mi)), Trient Glacier (4 km (2.5 mi)), the Bossons Glacier (c. 4 km (2.5 mi)) and the Brenva Glacier. Whilst these glaciers appear to show similar fluctuations in length, research shows that each glacier of the Mont Blanc massif has its own individual and distinctive response time to changes in snowfall and climate. The Bossons Glacier is known to respond first, then the Argentière and the Trient Glaciers respond four to seven years later, with the Mer de Glace reacting last —between eleven and fifteen years after changes are first observed in the movement of ice in the Bossons Glacier.

Even the smallest glaciers can have a significant impact on the environment and on human activity. In 1892, a large body of water which had accumulated under the surface of the Tête Rousse Glacier, burst suddenly on the night of 11 July. It released 200,000 cubic metres (7,100,000 ft3) of water and ice which flowed down the mountainside, killing 175 people in Saint-Gervais. The recent rediscovery of a further build-up of water deep within the glacier is now a cause of serious concern.

The inexorable downward movement and melting of glaciers can result in objects lost within them reappearing many years later. The first recorded account of a body reappearing from a glacier in the Mont Blanc range was made by Viscount Edmond de Catelin in 1861. It concerned three alpine guides who were buried in a crevasse during an avalanche on 20 August 1820 near the Rocher Rouges, high up on Mont Blanc, during an expedition organised by Joseph Hamel. Forty years later the remains of two of them were discovered, re-exposed within fissures in the Bossons glacier. They were 3,000 metres (9,800 ft) lower down from the point where they were lost; the corpse of the third guide was discovered the following year. In 2014, a group of climbers found a body on the Glacier du Talèfre, close to the Couvercle Hut. It was identified as that of a young Chamonix guide who had been caught in a winter storm during a solo ascent of the Nant Blanc face of the Aiguille Verte in 1982 and was assumed to have fallen into a crevasse. In 2013, a box of valuable gemstones was found by a climber on the Bossons Glacier. It had re-emerged, having been carried 3,048 metres (10,000 ft) downhill from the site of one of two Air India plane crashes. These occurred at almost identical locations high up near the summit of Mont Blanc: one in 1950 (Air India Flight 245), and one in 1966 (Air India Flight 101). Debris from these crashes is still commonly found on the glacier below.

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