Aletsch Glacier

The Great Aletsch Glacier is the area the largest and longest glacier in the Alps. It is located on the southern slopes of the Bernese Alps in the canton of Valais, Switzerland. The length of the glacier is 22.75 km, the area including the source Glacier is stated 81.7 km ². The Aletsch Glacier drained by the Massa into the Rhone. The area of ​​the entire catchment area of the massage is 195 km ², of which 1973 about two-thirds were glaciated. Often in the area indicate the upper and middle Aletsch be included, as they were formerly connected with the Great Aletsch Glacier. The total glaciated area including this glacier was in 1973 about 128 km ², for the year 1863 an area of ​​163 km ² is assumed.

Origin at Konkordiaplatz

The origin of the Great Aletsch Glacier is located in the 3,800 m high Jungfrau region. On Konkordiaplatz ( 46.5 ° N, 8.0366 ° E ) 46.5006478.0366432750, a 6 km ² large and only slightly sloping ice surface, flow three powerful Firnströme together:

• From the West leads the Aletschfirn, which flows along the northern foot of Aletschhorn and triangle horn. The Aletschfirn is fed from the north by three other important Firne, namely by the Ebnefluhfirn, the Gletscherhornfirn and Kranzbergfirn. All these Firne take its starting point at around 3800 m above sea level. M. Including the Ebnefluhfirns has the Aletschfirn to Konkordiaplatz a length of 9 km and is an average of nearly 1.5 km wide. To the west of the Aletschfirn is connected via the 3173 m high glacier pass Lötschenlücke with the long glacier that flows off into Loetschental.
• From the north-west flows of Jungfraufirn, although it is the direct continuation of the Aletsch Glacier, but the shortest of the three Tributärgletscher is. It has its origin on the southern flank of the monk, at the Jungfraujoch and on the eastern flank of the Virgin. Until Konkordiaplatz the Jungfraufirn travels a distance of just 7 km away and is thereby the west by Kranzberg, flanked to the east by Trugberg. It is in its upper part 2 km, below even just over 1 km wide.
• From north, the Ewigschneefeld, which takes its starting point on the eastern flank of the monk and in an arch, flanked by Trugberg in the west and the large Fiescherhorn and the greenhorn in the east, flows to Konkordiaplatz. Up to this point, it is about 8 km long and 1.2 km wide on average. The confluence with the Konkordiaplatz is via a steep slope with a gradient of 25 to 30%; the glacier is very rugged here. To the north, the Ewigschneefeld fissured hanging over the pass of the Lower Mönchsjochs ( 3529 m above sea level. M. ) with the catchment area of ​​the Lower Grindelwald glacier is associated. Through the Upper Mönchsjoch ( 3627 m above sea level. M. ) between the monk and the Trugberg is a connection to Jungfraufirn.

On Konkordiaplatz of East Far flows nor the much smaller Grüneggfirn (3 km long and on average 600 m wide). This is to the east across the glacier pass the Grünhornlücke ( 3280 m above sea level. M. ) connected to the Fieschergletscher.

Outcome

From Konkordiaplatz from the ice stream moves with a width of 1.5 km and a speed of up to 180 meters per year to the southeast in the Rhône Valley, bordered by the triangle horn in the west and the Great Horn When the east. He then draws a big right turn and turn more and more from the southwest, now separated by the ridge of the Eggishorn and Bettmerhorn from the Rhone Valley. The lowest part of the Great Aletsch Glacier is largely covered by glacial material from the side and medial moraines. The glacier is currently at 1,560 meters above sea level, far below the local tree line. From it springs the Massa stream, which, after the Massa Gorge and use in a hydroelectric power plant, in Bitche, above Naters, flows into the Rhone.

The Great Aletsch Glacier has considerable ice thickness. On Konkordiaplatz the glacier has an ice thickness of more than 900 meters to the south takes the thickness of the ice gradually to around 150 m from. Characteristic are the two dark, situated almost in the center of the Aletsch Glacier Moränenspuren, which extend along the entire length from the Konkordiaplatz up in the tongue area. They are the medial, which separate the ice of the three Hauptfirne each other. The western medial is also called Kranzbergmoräne, the eastern is called Trugbergmoräne.

Glacier fluctuations

In his High Stadium during the Little Ice Age in the mid- 19th century, the Great Aletsch Glacier stretched even 2.5 km down the valley. Due to the general warming since about 1870 he has particularly lost massively below the Konkordia space volume and released both on the sides and in the tongue area areas of several square kilometers size. The onetime, highest in modern times glacier level can be well estimated at almost barren moraines. Since 1850, the ice thickness has decreased by some 100 m. Previously, the ice streams of the upper Aletsch Glacier Aletsch Glacier and the middle were directly connected to the Great Aletsch Glacier.

In the valley between the beam and the horn Eggishorn the Märjelensee, which was dammed to form a Gletscherrandsee in the 19th century the glacier high level is. His repeated sudden outbreaks caused by crevasses and over again strong damage flood of Massa towards the Rhone Valley.

Against short-term climate fluctuations of glaciers is relatively immune because of its large mass. While many other glaciers were advancing end of the seventies to the early eighties, the Aletsch Glacier hardly reacted to the temporary cooling - just as the warm years since 1983 due to the increasingly extreme heat of the past few years but he prefers now but -. As all other Alpine glaciers - significantly strengthened back.

The relative inertia in its response to climate variability makes the Aletsch Glacier also an ideal study object for the study of climate change in the Alps. The length variations of the Aletsch Glacier in the past are likely to even allow a reconstruction of all major climate changes of the past 3200 years. The determination of the different stages of the Aletsch glacier length in the past done by the radiocarbon dating of fossil tree trunks that have passed across the glacier at an earlier foray once and has now released again during his recent retreat. The finding of fossil soils and root system guarantees that it is the locality is also about the growth location of the fossil tree. By counting the annual rings of the salvaged logs can even be determined by the period during which the Aletsch glacier has not reached the locality. With this method, it was found that the Aletsch glacier must have been a lot smaller BC to about 1200 than today. For the years around 1200-1110 BC, 850-750 BC and 350-250 BC initiatives have been identified. Here, the Aletsch Glacier 900-400 BC, however, been smaller than it is today, as well as from about 100 BC until the year 250 Around the year 300 a glacier length is comparable to the maximum level in the 19th century noted.

Tourism

The Aletsch Glacier was early on as a special attraction for travelers and as a welcome object of investigation for researchers. Research stations there are on the Jungfraujoch since 1976 Riederfurka above the Riederalp since 1937. Particularly well served by numerous cable cars of the ridge between the Riederhorn and the Eggishorn, the very beautiful insights into the tongue area and the lower part of the glacier is granted. With the construction of the Jungfrau Railway to the Jungfraujoch ( 3571 m above sea level on the Sphinx. M. ) a view of the upper part of the glacier in 1912 for non- mountain familiar people possible.

On the rocky slope of the mountain east of the digester Konkordia place are 2850 m above sea level. M. Konkordia the cottages of the Swiss Alpine Club SAC. They serve as an important stage on the high alpine glacier route from the Jungfraujoch or the Loetschental in the area of the Grimsel Pass.

UNESCO World Heritage Site

The area of ​​the Great Aletsch Glacier is combined with the unique Aletsch forest and surrounding regions since 13 December 2001, part of the UNESCO World Heritage Swiss Alps Jungfrau -Aletsch.