Aletsch Glacier

The Aletsch Glacier (German: Aletschgletscher [altltr] ) or Great Aletsch Glacier (Grosser Aletschgletscher) is the largest glacier in the Alps. It has a length of about 23 km (14 mi) (2014), a volume of 15.4 km3 (3.7 cu mi) (2011), and covers about 81.7 km2 (31.5 square miles) (2011) in the eastern Bernese Alps in the Swiss canton of Valais. The Aletsch Glacier is composed of four smaller glaciers converging at Konkordiaplatz, where its thickness was measured to reach a maximum of 905 metres (2,969 ft). It then continues towards the Rhône valley before giving birth to the Massa. The Aletsch Glacier is – like most glaciers in the world today – a retreating glacier. As of 2016, since 1980 it lost 1.3 kilometres (0.81 mi) of its length, since 1870 3.2 kilometres (2.0 mi), and lost also more than 300 metres (980 ft) of its thickness. The whole area, including other glaciers is part of the Jungfrau-Aletsch Protected Area, which was declared a UNESCO World Heritage Site in 2001.

The Aletsch Glacier is one of the many glaciers located between the cantons of Bern and Valais on the Bernese Alps located east of the Gemmi Pass. The whole area is considered to be the largest glaciated area in western Eurasia. The Fiescher and Aar Glaciers lying on the east have similar extensions.

Except the Finsteraarhorn, all the highest summits of the Bernese Alps are located within the drainage basin of the glacier. The Jungfrau and Mönch constitute the northern boundary; the Gross Fiescherhorn and Gross Wannenhorn lie on its east side; finally the culminating point, the Aletschhorn (4,193 m (13,757 ft)) is located on the west side. Before reaching the maximum flow, four smaller glaciers converge at Konkordiaplatz:

From the western mouth flows the Grosser Aletschfirn, which runs along the northern foot of the Aletschhorn and Dreieckhorn. The Grosser Aletschfirn is supplied from the north by three notable firns: the Äbeni Flue-Firn, the Gletscherhornfirn, and the Kranzbergfirn. All of these firns have their starting points at around 3,800 m (12,500 ft). From the Äbeni Flue-Firn to the Konkordiaplatz, the Grosser Aletschfirn is 9 km (5.6 mi) long and is on average about 1.5 km (0.93 mi) wide. On the west, the Grosser Aletschfirn connects with the Langgletscher over the 3,158 m (10,361 ft) high glacier pass, the Lötschenlücke, into the Lötschental. 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 four tributary glaciers. It has its origin on the southern flank of the Mönch and at the eastern flank of the Jungfrau with the Jungfraujoch in-between. Up to the Konkordiaplatz, the Jungfraufirn is a scarce 7 km (4.3 mi) long, and returns to flank the Kranzberg in the west and the Trugberg in the east. At its highest point, it is 2 km (1.2 mi) wide, and further down it is still a good 1 km (0.62 mi) wide. From the northern mouth flows the Ewigschneefäld ("Eternal snow field"), where its starting point takes the east flank of the Mönch. In an elbow, it flanks from Trugberg in the west and the Gross Fiescherhorn and Grünhorn in the east, flowing on to the Konkordiaplatz. Up to here, it is about 8 km (5.0 mi) long and averages about 1.2 km (0.75 mi) wide. The mouth at the Konkordiaplatz it follows over a rise with a descent from 25 to 30 percent; here, the glacier is sharply split. Against the north is the Ewigschneefäld over the snow-covered pass of the Unners Mönchsjoch (3,518 m (11,542 ft)), connected with the catchment area of the Ischmeer (Wallis German for "Ice Sea"). Through the Obere Mönchsjoch (3,624 m (11,890 ft)) between the Mönch and the Trugberg stands a connection to the Jungfraufirn. From the east, the smallest firn arrives at the Ko

Glacier data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).