'Aletsch Glacier', the largest
glacier in the
Alps, covers more than 120 square kilometres (more than 45 square miles) in southern
Switzerland. It descends round the south of the Jungfrau into the valley of the Upper Rhône; at its eastern extremity lies a glacier lake,
Lake Märjelen (Gr. Märjelensee) (2,350 meters/7,711 feet above sea level). To the west rises
Aletschhorn (4,195 meters/13,763 feet), which was first climbed in
1859. The
Rhône River flows along the southern flank of the mountains.
Description
★ From the western mouth flows the 'Great Aletschfirn', which runs along the northern foot of the
Aletschorn and
Dreieckhorn. The
Aletschfirn is supplied from the north by three notable
firns: the
Ebnefluhfirn, the
Gletscherhornfirn, and the
Kranzberfirn. All of these Firns have their starting points at around 3800 m. From the Ebnefluhfirns to the
Konkordiaplatz, the Aletschfirn is 9 km long and is on average about 1.5 km wide. From the west, the Aletschfirn flows over the 3173 m high
Gletscherpass, the
"Lötschenlücke", connecting with the
Langgletscher, and then into the
Lötschental valley.
★ From the northwestern mouth flows the 'Jungfraufirn'. This firn in fact represents the straight continuation of the Aletsch Glacier, yet is the shortest of the three tributary glaciers. It has its origin on the southern flank of the
Mönch, at the Jungfraujoch and at the eastern flank of the Jungfrau. Up to the Konkordiaplatz, the Jungfraufirn is a scarce 7 km long, and returns to flank the
Kranzberg in the west and the
Trugberg in the east. At its highest point, it is 2 km wide, and further down it is still a good 1 km wide.
★ From the northern mouth flows the 'Ewigschneefeld' (Eternal snow field), where its starting point takes the east flank of the Mönchs. In an elbow, it flanks from Trugberg in the west and the
Fiescherhorn and
Grünhorn in the east, flowing on to the
Konkordiaplatz. Up to here, it is about 8 km long and averages about 1.2 km wide. The mouth at the Konkordplatz it follows over a rise with a descent from 25 to 30 percent; here, the glacier is sharply split. Against the north is the Ewigschneefeld over the snow-covered pass of the ''Lower Mönchsjochs'' (3529 m high), connected with the catchment area of the ''Lower Grindelwald'' glacier. Through the ''Higher Mönchsjoch'' (3627 m high) between the Mönch and the Trugberg stands a connection to the Jungfraufirn.
Also at the mouth of the Konkordiaplatz from the east is the small but important 'Grüneggfirn' (3 km long and averaging 600 m wide). This firn is connected in the over the glacier pass ''Grünhornlücke'' (3280 m high) to the
Fiescher Glacier in the east.
From the Konkordiaplatz, the Aletsch Glacier has a width of approximately 1.5 km and moves at a rate of 180 m per year to the southeast on course with the
Rhône valley, bordering the Dreieckhorn in the west and the great
Wannenhorn in the east. It then takes a great right turn and bends ever closer to the southwest, running through the edge of the
Eggishorn and
Bettmerhorn of the Rhone valley. The lowest part of the great Aletsch Glacier is largely covered with detritus of the lateral and medial
moraines. The glacier's toe currently lies about 1560 m high, far beneath the local tree line. From it springs the Massa stream, which flows though the Massa Canyon and is used to generate hydroelectric power. It continues through the upper half of the
Brig, eventually entering into the Rhone.
The great Aletsch Glacier shows considerable ice cover. At the Konkordiaplatz, it has an ice cover of more than 900 m, but as it moves to the south, the greater part of the ice melts, gradually decreasing the cover to around 150 m.
The characteristically dark medial moraine, situated almost in the middle of the glacier, runs protracted in two bands from the Konkordiaplatz along the whole length to the glacier's toe-zone. This medial moraine is collected from the ice of three large ice fields, which all run together. The westernmost medial moraine has been named the ''Kranzbergmoräne'', and the easternmost carries the name ''Trugbergmoräne''.

Aletsch Glacier during summer
Recent retreat
Only slight
retreat and some thinning are evident over this short repeat photo interval, but records show a major longer-term retreat trend
[1][2].
On August 18th, 2007, photographer
Spencer Tunick used hundreds of naked people in a "living sculpture" on Aletsch Glacier in a photo shoot intended to draw attention to
global warming and the shrinking of the world's glaciers. The termperature was about 50 degrees Fahrenheit at the time of the time of the photo shoot. The 600 participants on the shrinking glacier volunteered for Tunick (a collaboration with Greenpeace) to let the world know about the effects of
global warming on the melting Swiss glaciers, which are predicted to disappear by 2080. The Aletsch glacier fell by 115m on 2005 and 2006.
[1]
See also
★
List of glaciers
External links
★
Aletsch glacier on Google Maps
★
Panoramic drawing of area including hikes
References
1. Guardian Unlimited, Say freeze: why 600 people stripped and posed on a Swiss glacier