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The Glacier Blanc is a
The Glacier Blanc begins on the northern slopes of the most southwesterly of the four-thousanders in the
With its 5.9 km-long tongue (in 2002), the Glacier Blanc is the longest glacier in the
glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...
in the French département of Hautes-Alpes
Hautes-Alpes (; oc, Auts Aups; en, Upper Alps) is a department in the Provence-Alpes-Côte d'Azur region of Southeastern France. It is located in the heart of the French Alps, after which it is named. Hautes-Alpes had a population of 141,220 ...
. Its name (which means "white glacier") derives from the fact that – unlike the nearby Glacier Noir
The Glacier Noir ( French for "black glacier") is a glacier in the Massif des Écrins in the French Alps. It is located in the département of Hautes-Alpes.
Geography
Of all the great glaciers in the Oisans region, the Glacier Noir is the one th ...
("black glacier") – its surface appears pristinely white due to an absence of morainic
A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice she ...
debris.
A glacier that is largely free of such moraines is generally described in French as a ''glacier blanc''.
See
Geography
The Glacier Blanc begins on the northern slopes of the most southwesterly of the four-thousanders in the Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Swi ...
, the high Barre des Écrins
The Barre des Écrins () is a mountain in the French Alps with a peak elevation of . It is the highest peak of the Massif des Écrins and the Dauphiné Alps and the most southerly alpine peak in Europe that is higher than 4,000 metres. It is the ...
. It is separated from the Glacier Noir to the south by the crest of ''Crête de l'Encoula'' (or ''Crête de l'Encula''), that runs from the Barre des Écrins to the ''Pointe du Serre Subeyran''. The upper part of the glacier is sometimes named ''Glacier de l'Enc(o)ula'' after this arête
An arête ( ) is a narrow ridge of rock which separates two valleys. It is typically formed when two glaciers erode parallel U-shaped valleys. Arêtes can also form when two glacial cirques erode headwards towards one another, although frequ ...
; on several older maps, this name is used for the whole glacier.Website of Kommune Pelvoux in VallouiseWith its 5.9 km-long tongue (in 2002), the Glacier Blanc is the longest glacier in the
Massif des Écrins
The mountains of the Massif des Écrins (; Écrins Massif) form the core of Écrins National Park in Hautes-Alpes and Isère in the French Alps. is not, however, as great as that of the Glacier de la Girose and the Glacier du Mont-de-Lans, which form a common system. The Glacier Blanc is a typical valley glacier, which initially runs in a curve towards the northeast below the Barre, before its tongue turns southeast, becoming an 
In its centre section, the main stream (excluding side glaciers) of the Glacier Blanc is about 800 to 1000 metres wide. The greatest depth of ice occurs at the Refuge des Écrins where it is up to 250 metres deep, some 30 metres less than it was in 1985. – Contains a well-drawn diagram of a longitudinal section through the glacier The glacier flows at a speed of around 40 metres per year in its central section (in the mid-1980s it moved at 50 m/yr) and about 30 metres per year near its snout. Its reaction time, i.e. the time that elapses before the foot of the glacier advances or retreats due to major changes in conditions in the accumulation zone, is about 6 years in the case of the Glacier Blanc. From its head at over high to its foot, currently (2010) at about (2002: ), the Glacier Blanc descends through a height of around 1,600 metres.
The 
As with almost all alpine glaciers, the foot of the Glacier Blanc has retreated. In earlier times, most recently in 1866,
According to other sources 1876 was the year that the Glacier Blanc and Glacier Noir were separated, c.f.
it formed a single glacial system with its southern neighbour, the moraine-covered Glacier Noir, whose streams joined one another above the ''Pré de Madame Carle''. During the Little Ice Age, the combined ice system reached its maximum extent in 1815 and ended roughly at the height of the ''Cezanne Hut'' ().
As of 2010, the tongue of the Glacier Blanc lies at a height of about . In the 20th century, it is estimated that it retreated by about 1 km, accompanied by a reduction in area of some 2 km2. Between 1989 and 1999 alone, the glacier lost about 210 metres; it retreated a further 300 metres in the years to 2006.c.f
Description at vallouimages.com
/ref> The ice thickness in the centre reduced during the period from 1981 to 2002 by 13.5 metres, an estimated loss in volume of 70 million m³ of ice.
(French)
(French) * ttp://warpinghistory.blogspot.co.uk/2012/07/disappearing-acts-life-and-death-of.html Historical study of the Glacier Blanc Glaciers of the Alps Glaciers of Metropolitan France GBlanc Landforms of Provence-Alpes-Côte d'Azur
icefall
An icefall is a portion of certain glaciers characterized by relatively rapid flow and chaotic crevassed surface, caused in part by gravity. The term ''icefall'' is formed by analogy with the word ''waterfall'', which is a similar phenomenon of ...
. Its average incline is about 30%, but it is flatter in its central section than on the north slope of the Barre des Écrins or in the icefall of its lower section.
The glacier is bounded on its orographically left-hand side by, ''inter alia'', the summits of the Roche Faurio (), Pic de Neige Cordier () and the Montagne des Agneaux (). The ''Crête de l'Encoula'' forms the southern boundary, running from the Barre des Écrins over ''Barre Noir'' (), Pointe Mettrier () and Pointe de la Grande Sagne () to the Pointe du Serre Subeyran (). Between the peaks that surround the glacial basin are smaller side glaciers that feed the main stream.
In its centre section, the main stream (excluding side glaciers) of the Glacier Blanc is about 800 to 1000 metres wide. The greatest depth of ice occurs at the Refuge des Écrins where it is up to 250 metres deep, some 30 metres less than it was in 1985. – Contains a well-drawn diagram of a longitudinal section through the glacier The glacier flows at a speed of around 40 metres per year in its central section (in the mid-1980s it moved at 50 m/yr) and about 30 metres per year near its snout. Its reaction time, i.e. the time that elapses before the foot of the glacier advances or retreats due to major changes in conditions in the accumulation zone, is about 6 years in the case of the Glacier Blanc. From its head at over high to its foot, currently (2010) at about (2002: ), the Glacier Blanc descends through a height of around 1,600 metres.
The firn line
__NOTOC__
Firn (; from Swiss German "last year's", cognate with ''before'') is partially compacted névé, a type of snow that has been left over from past seasons and has been recrystallized into a substance denser than névé. It is ice that ...
on the Glacier Blanc, which separates the accumulation zone from the ablation zone
Ablation zone or ''ablation area'' refers to the low-altitude area of a glacier or ice sheet below firn with a net loss in ice mass due to melting, sublimation, evaporation, ice calving, aeolian processes like blowing snow, avalanche, and any ...
, lies on the northern slopes at a height of about and on the southern flanks at about . The glacier's mass balance
In physics, a mass balance, also called a material balance, is an application of conservation of mass to the analysis of physical systems. By accounting for material entering and leaving a system, mass flows can be identified which might have b ...
, an indicator of its health, has not been fully investigated.
The Glacier Blanc drains via the ''Torrent du Glacier Blanc'', the ''Gyr'', the Gyronde, the Durance, and finally the Rhône
The Rhône ( , ; wae, Rotten ; frp, Rôno ; oc, Ròse ) is a major river in France and Switzerland, rising in the Alps and flowing west and south through Lake Geneva and southeastern France before discharging into the Mediterranean Sea. At Ar ...
into the Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
.
Access
From ''Pré de Madame Carle'' and its ''Refuge Cézanne'' hut, where the road from the village ofAilefroide
The Ailefroide (3,954 m) is a mountain in the Massif des Écrins in the French Alps, and is the third highest peak in the Dauphiné Alps after the Barre des Écrins and La Meije. It lies at the south-western end of the Mont Pelvoux–Pic Sans No ...
in the Vallouise ends at a large car park, a popular alpine walking trail runs up to the ''Refuge du Glacier Blanc'' (), from where the glacier is visible. Around 100 metres lower down the trail passes the ''Ancien Refuge Tuckett'', a small accommodation hut from the end of the 19th century. This primitive hut, that today is an exhibit, was built immediately next to a large stone slab that had hitherto acted as a camping place from which the area could be explored. The shelter was named the ''Hotel Tuckett'', after the alpinist Francis Fox Tuckett
Francis Fox Tuckett FRGS (10 February 1834 – 20 June 1913)D.W.F., 'Obituary: Francis Fox Tuckett' in ''The Geographical Journal'', Vol. 42, No. 2 (August 1913), pp. 206–207 was an English mountaineer. He was vice-president of the Alpine Club ...
.
Two hours by foot further on the ''Refuge des Écrins'' is situated high above the Glacier Blanc on a prominent rocky 'pulpit', at a height of , with expansive views of the area. The hut trail runs for the most part immediately above the glacier and should only be attempted by fully equipped high-altitude alpinists because of the danger of falling into a crevasse
A crevasse is a deep crack, that forms in a glacier or ice sheet that can be a few inches across to over 40 feet. Crevasses form as a result of the movement and resulting stress associated with the shear stress generated when two semi-rigid pie ...
. The high alpine base with 119 beds is often overbooked during the peak season.
From La Bérarde (), the alpinist centre in the Haut Vénéon, the Glacier Blanc may be reached over the ''Col des Écrins'' () at the end of the ''Val de Bonne Pierre''. This is a day's tour at grade
Grade most commonly refers to:
* Grade (education), a measurement of a student's performance
* Grade, the number of the year a student has reached in a given educational stage
* Grade (slope), the steepness of a slope
Grade or grading may also ref ...
PD. The western approach to the col is steep and challenging, although wire cables improve safety in its upper section. On the eastern side, the Glacier Blanc reaches right up to the narrow wind gap.
Historic development
As with almost all alpine glaciers, the foot of the Glacier Blanc has retreated. In earlier times, most recently in 1866,
According to other sources 1876 was the year that the Glacier Blanc and Glacier Noir were separated, c.f.
it formed a single glacial system with its southern neighbour, the moraine-covered Glacier Noir, whose streams joined one another above the ''Pré de Madame Carle''. During the Little Ice Age, the combined ice system reached its maximum extent in 1815 and ended roughly at the height of the ''Cezanne Hut'' ().
As of 2010, the tongue of the Glacier Blanc lies at a height of about . In the 20th century, it is estimated that it retreated by about 1 km, accompanied by a reduction in area of some 2 km2. Between 1989 and 1999 alone, the glacier lost about 210 metres; it retreated a further 300 metres in the years to 2006.c.fDescription at vallouimages.com
/ref> The ice thickness in the centre reduced during the period from 1981 to 2002 by 13.5 metres, an estimated loss in volume of 70 million m³ of ice.
References
External links
* * {{cite web , author1=Hervé Cortot , author2=Marcel Chaud , publisher=L'Association des Professeurs de Biologie et Géologie Aix-Marseille , url=http://www.apbg.org/aix/docs//GLBPP2p.doc , title=Le glacier Blanc , language=fr , date=Jul 2005 , format=doc , access-date=29 Sep 2010 , url-status=dead , archiveurl=https://web.archive.org/web/20110904045032/http://www.apbg.org/aix/docs//GLBPP2p.doc , archivedate=2011-09-04 – Contains a good diagram of a longitudinal section through the glacier(French)
(French) * ttp://warpinghistory.blogspot.co.uk/2012/07/disappearing-acts-life-and-death-of.html Historical study of the Glacier Blanc Glaciers of the Alps Glaciers of Metropolitan France GBlanc Landforms of Provence-Alpes-Côte d'Azur