Mer de Glace

Interesting facts

In the 17th century, as the glacier advanced toward homes in the valley, local people held processions and exorcisms to make it stop.

Counting all its tributaries, it is France's longest and largest glacier and the second longest in the Alps after the Aletsch.

On 24 July 1842 James David Forbes noticed light and dark bands on its surface and began to consider that glaciers flow like a viscous river.

In 1840 the canon Louis Rendu observed that the centre of the glacier moves faster than its edges, a key early insight into how ice flows.

Crevasses in the glacier can be up to 50 m deep, and pressure within the ice reaches at least 30 atmospheres.

Since 1973 a hydroelectric plant has tapped meltwater from beneath the glacier; after retreat stranded the intake, a new one was built in 2011 under about 100 m of ice.

Sand carried in the meltwater wears out the turbine of the Les Bois power station so quickly that it has to be replaced every year.

In 1986 Janot Lamberton and Jean-Marc Boivin descended 110 m into a moulin in the glacier, doubling a depth record set in 1897.

The Arveyron river once burst from a 20–25 m wide ice cave at the glacier's snout, painted by many artists before it probably collapsed in 1873.

Frankenstein's glacier scenes inspired Richard Meale's 1991 opera Mer de glace, with a libretto by David Malouf.

Why it is worth it

The Mer de Glace, the "sea of ice", is a river of ice about 7 km long, or some 12 km if its feeder glaciers are counted, flowing down the northern side of the Mont Blanc massif towards the Chamonix valley. Seen from the Montenvers terrace at 1,913 metres, it curves away between the granite spires of the Drus and the wall of the Grandes Jorasses, its surface ribbed and crevassed and darkened by rock debris.

The glacier forms where the Glacier de Leschaux and the Glacier du Tacul meet at around 2,100 metres, and it is fed from above by the Talèfre and Géant glaciers and the snowfields of the Vallée Blanche. In places the ice is up to 300 metres thick. Its name is usually traced to two British travellers, William Windham and Richard Pococke, who climbed up from Chamonix in 1741 and compared the surface to a lake whipped up by wind and suddenly frozen; their account, published in 1744, helped launch Chamonix as a destination. Goethe, Victor Hugo and John Ruskin all came to see it, and Mary Shelley set two meetings between Victor Frankenstein and his creature on the glacier in Frankenstein (1818).

The Mer de Glace is also one of the most closely watched records of glacial retreat in the Alps. In the eighteenth and early nineteenth centuries its snout reached down almost to the valley floor at the hamlet of Les Bois, and it reached its greatest modern extent around the middle of the nineteenth century. Since then it has shortened by roughly 3 km, and between 1905 and 2005 its surface near Montenvers dropped by about 120 metres. The rack railway from Chamonix, opened in 1909, has had to be followed by a cable car (1961) and long stairways as the ice sank further below the old viewpoint. Each year a new ice cave is carved into the glacier, a tradition at Montenvers since 1946.

Getting there

The glacier lies above Chamonix-Mont-Blanc in the Haute-Savoie department of France. The Montenvers rack railway climbs 5.1 km from Chamonix (1,042 m) to Montenvers (1,913 m) in about 20 minutes. Among larger towns, Sallanches in France and Martigny in Switzerland are each about 23–24 km away in a straight line. The nearest airport is Annecy (NCY), about 65 km in a straight line; Geneva Airport (GVA), about 88 km from Chamonix, is the main international gateway for the valley.

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From the encyclopaedia

The Mer de Glace is a valley glacier located on the northern slopes of the Mont Blanc massif, in the French Alps. It is 7.5 km long and 200 metres (660 ft) deep, but when all its tributary glaciers are taken into account, it can be regarded as the longest and largest glacier in France, and the second longest in the Alps after the Aletsch Glacier.

I can no otherwise convey to you an image of this body of ice, broken into irregular ridges and deep chasms than by comparing it to waves instantaneously frozen in the midst of a violent storm.

Wikipedia · CC BY-SA 4.0

Interesting facts

Why it is worth it

Getting there

Plan your visit

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From the encyclopaedia