Aletsch Glacier

{{Infobox glacier

| name = Aletsch Glacier

| other_name = (Grosser) Aletschgletscher

| photo = Switzerland, Bettmeralp (19505442736).jpg

| photo_caption = Aletsch Glacier in June 2011

| type = Valley glacier

| location = Valais, Switzerland

|coordinates = {{coord|46|26|32|N|8|4|38|E|format=dms|display=inline,title}}

| map_caption = Location in Switzerland

| area = {{convert|81.7|km2|abbr=in}} (2011)

| length = {{convert|22.6|km|abbr=in}} (2014)

| thickness = 940 m ({{lang|de|Konkordiaplatz}})

| elevation_max = 4160 m

| elevation_min = 1650 m

| terminus = Massa

| status = Retreating

| map = Switzerland#Alps

| label_position = top

| map_alt =

| embedded = {{Infobox mapframe |wikidata=yes |zoom=12 |coord={{WikidataCoord|display=i}}}}

}}

The Aletsch Glacier ({{langx|de|Aletschgletscher}}, {{IPA|de|ˈalɛtʃˌɡlɛtʃɐ}}) or Great Aletsch Glacier ({{lang|de|Grosser Aletschgletscher}}) is the largest glacier in the Alps. It has a length of about {{convert|23|km|abbr=on}} (2014), a volume of {{convert|15.4|km3|abbr=on}} (2011), and covers about {{convert|81.7|km2|abbr=in}} (2011) in the eastern Bernese Alps in the Swiss canton of Valais.{{cite web |url=https://www.aletscharena.ch/naturphaenomen/unesco/gletscherwelten.pdf |title=World of glaciers |publisher=Stiftung UNESCO Welterbe Schweizer Alpen Jungfrau-Aletsch, Managementzentrum |editor=Andres Betschart |date=2011 |edition=1 |location=Naters, Switzerland |language=de, en |access-date=2016-02-14 |archive-url=https://web.archive.org/web/20160414151536/https://www.aletscharena.ch/naturphaenomen/unesco/gletscherwelten.pdf |archive-date=14 April 2016 |url-status=dead }} The Aletsch Glacier is composed of four smaller glaciers converging at Konkordiaplatz, where its thickness was measured by the ETH to be still near {{convert|1|km|ft|abbr=on}}.{{citation needed|date=February 2016}} It then continues towards the {{lang|fr|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 {{convert|1.3|km}} of its length, since 1870 {{convert|3.2|km}}, and lost also more than {{convert|300|m}} 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.

Geography

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.{{cite web |url=https://whc.unesco.org/en/list/1037/ |title=Swiss Alps Jungfrau-Aletsch |publisher=UNESCO World Heritage Centre 1992-2016, UN |website=unesco.org |date=13 December 2001 |location=Paris, France |access-date=2016-03-18}} The Fiescher and Aar Glaciers lying on the east have similar extensions.

File:Aletschhorn from Konkordia.jpg

File:Massa river.jpg (the glacier is visible on the right)]]

File:Aletsch_Glacier_(Jungfraufirn).jpg

Except the {{lang|de|Finsteraarhorn}}, all the highest summits of the Bernese Alps are located within the drainage basin of the glacier. The {{lang|de|Jungfrau}} and {{lang|de|Mönch}} constitute the northern boundary; the {{lang|de|Gross Fiescherhorn}} and {{lang|de|Gross Wannenhorn}} lie on its east side; finally the culminating point, the {{lang|de|Aletschhorn}} ({{convert|4193|m|abbr=on}}) is located on the west side.

Before reaching the maximum flow, four smaller glaciers converge at Konkordiaplatz:

From the western mouth flows the {{lang|de|Grosser Aletschfirn}}, which runs along the northern foot of the {{lang|de|Aletschhorn}} and {{lang|de|Dreieckhorn}}. The {{lang|de|Grosser Aletschfirn}} is supplied from the north by three notable firns: the {{lang|de|Äbeni Flue-Firn}}, the {{lang|de|Gletscherhornfirn}}, and the {{lang|de|Kranzbergfirn}}. All of these firns have their starting points at around {{convert|3800|m|abbr=on}}. From the {{lang|de|Äbeni Flue-Firn}} to the {{lang|de|Konkordiaplatz}}, the {{lang|de|Grosser Aletschfirn}} is {{convert|9|km|abbr=on}} long and is on average about {{convert|1.5|km|abbr=on}} wide. On the west, the {{lang|de|Grosser Aletschfirn}} connects with the Langgletscher over the {{convert|3158|m|abbr=on}} high glacier pass, the {{lang|de|Lötschenlücke}}, into the {{lang|de|Lötschental}}.
From the northwestern mouth flows the {{lang|de|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 {{lang|de|Mönch}} and at the eastern flank of the {{lang|de|Jungfrau}} with the {{lang|de|Jungfraujoch}} in-between. Up to the {{lang|de|Konkordiaplatz}}, the {{lang|de|Jungfraufirn}} is a scarce {{convert|7|km|abbr=on}} long, and returns to flank the {{lang|de|Kranzberg}} in the west and the {{lang|de|Trugberg}} in the east. At its highest point, it is {{convert|2|km|abbr=on}} wide, and further down it is still a good {{convert|1|km|abbr=on}} wide.
From the northern mouth flows the {{lang|de|Ewigschneefäld}} ("Eternal snow field"), where its starting point takes the east flank of the {{lang|de|Mönch}}. In an elbow, it flanks from {{lang|de|Trugberg}} in the west and the {{lang|de|Gross Fiescherhorn}} and {{lang|de|Grünhorn}} in the east, flowing on to the {{lang|de|Konkordiaplatz}}. Up to here, it is about {{convert|8|km|abbr=on}} long and averages about {{convert|1.2|km|abbr=on}} wide. The mouth at the {{lang|de|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 {{lang|de|Ewigschneefäld}} over the snow-covered pass of the {{lang|de|Unners Mönchsjoch}} ({{convert|3518|m|abbr=on}}), connected with the catchment area of the {{lang|swg|Ischmeer}} (Wallis German for "Ice Sea"). Through the {{lang|de|Obere Mönchsjoch}} ({{convert|3624|m|abbr=on}}) between the {{lang|de|Mönch}} and the {{lang|de|Trugberg}} stands a connection to the {{lang|de|Jungfraufirn}}.
From the east, the smallest firn arrives at the {{lang|de|Konkordiaplatz}}: the {{lang|de|Grüneggfirn}}. Its northern arm begins below the {{lang|de|Grünegghorn}} ({{convert|3860|m|abbr=on}}). The southern arm collects its snow and ice in the pot flanked by the {{lang|de|Wyssnollen}}, {{lang|de|Fiescher Gabelhorn}} ({{convert|3866|m|abbr=on}}), and the {{lang|de|Chamm}}. Between the peaks {{lang|de|Wyssnollen}} and {{lang|de|Grünhörnli}} another glacier pass, the {{lang|de|Grünhornlücke}} ({{convert|3279|m|abbr=on}}), connects to the {{lang|de|Fieschergletscher}}. The {{lang|de|Grüneggfirn}} enters the {{lang|de|Konkordiaplatz}} in a gap between the mountainsides {{lang|de|Grünegg}} to the north and the {{lang|de|Fülberg}} to the south. On the western side of the {{lang|de|Fülberg}} the Konkordia hut (mountain hut) overlooks the whole {{lang|de|Konkordiaplatz}} at an altitude of {{convert|2850|m|abbr=on}}.

South of Konkordiaplatz, the glacier runs towards the valley of the {{lang|de|Oberwallis}} (Upper Valais); on the east side, near {{lang|de|Bettmeralp}}, lies a small glacier lake, {{lang|de|Märjelensee}} ({{convert|2301|m|ft|abbr=in}}); from the western side used to enter the {{lang|de|Mittelaletschgletscher}}, but since the end of the 20th century the connection with the Aletsch Glacier has been lost. Further down, until about 1880, the {{lang|de|Oberaletschgletscher}} did also enter the Aletsch Glacier at its mouth. But since then both glaciers have been retreating so far that they do not connect anymore (the Upper Aletsch Glacier did retreat about {{convert|1.3|km|abbr=on}} from its connecting point with the Aletsch Glacier), but both serve now only as the source of the river Massa. The river flows through the Stausee Gibidum (a reservoir, and coincidentally representing the glacier's mouth region in the 19th century, which is a retreat of more than {{convert|4|km|abbr=on}}) and a gorge of the same name before reaching the {{lang|fr|Rhône}} near {{lang|de|Brig}}.

Tourism

The area of the Aletsch Glacier and some surrounding valleys is on the UNESCO World Heritage list, thus it is protected and the facilities are mostly restricted to the external zones. The region between {{lang|de|Belalp}}, {{lang|de|Riederalp}} and {{lang|de|Bettmeralp}} (which is called Aletsch Region) in Valais gives access to the lower part of the glacier. The {{lang|de|Bettmerhorn}} and {{lang|de|Eggishorn}} are popular view points and are accessible by cable car. The {{lang|de|Massa}} river can be crossed since 2008 by a suspension bridge, thus allowing hikes between the left and the right part of the glacier.

The {{lang|de|Jungfraujoch}} railway station (3,450 m) gives a direct access to the upper Aletsch Glacier as well as the normal route to the {{lang|de|Jungfrau}}. It can be reached only from {{lang|de|Interlaken}} in the canton Bern. Hiking paths pass the Konkordia Hut or the Hollandia Hut, eventually reaching other glaciers in the massif.

On the {{lang|de|Riederfurka}}, at 2,065 metres between {{lang|de|Riederalp}} and the glacier, is located the historic Villa Cassel, former summer residence of many famous and influential guests from the worlds of politics and finance. The house is now one of the centers of the environmental organization Pro Natura, which hosts a permanent exhibition about the site.{{cite web |url=http://www.pronatura.ch/aletsch/en/center/exhibition.html |title=The Pro Natura Center Aletsch – History |publisher=Pro Natura Center Aletsch |location=Riederalp, VS, Switzerland |website=pronatura.ch |access-date=2016-03-18 |archive-url=https://web.archive.org/web/20090813132238/http://www.pronatura.ch/aletsch/en/center/exhibition.html |archive-date=13 August 2009 |url-status=dead }}

Panorama

Image:070915 Panorama Aletschgletscher von Konkordiahütte.jpg (Sept. 2007)]]

Also at the mouth of the {{lang|de|Konkordiaplatz}} from the east is the small but important {{lang|de|Grüneggfirn}} (3 km long and averaging 600 m wide). This firn is connected in the over the glacier pass {{lang|de|Grünhornlücke}} (3280 m high) to the Fiescher Glacier in the east.

From the {{lang|de|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 {{lang|fr|Rhône}} valley, bordering the {{lang|de|Dreieckhorn}} in the west and the great {{lang|de|Wannenhorn}} in the east. It then takes a great right turn and bends ever closer to the southwest, running through the edge of the {{lang|de|Eggishorn}} and {{lang|de|Bettmerhorn}} of the Rhône 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 through the Massa Canyon and is used to generate hydroelectric power. It continues through the upper half of the {{lang|de|Brig}}, eventually entering into the {{lang|fr|Rhône}}.

File:Eggishorn panorama.jpg}} (Sept. 2007)]]

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 {{lang|de|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 {{lang|de|Kranzbergmoräne}}, and the easternmost carries the name {{lang|de|Trugbergmoräne}}.

Formation and evolution

File:Aletsch Glacier animation.gif

The Aletsch Glacier resulted from the accumulation and compaction of snow. Glaciers generally form where snow and ice accumulation exceed snow and ice melt. As the snow and ice thicken it reaches a point where it begins to move due to a combination of gravity and pressure of the overlying snow and ice.

During the last glacial periods, the Aletsch Glacier was much larger than now. 18,000 years ago the lower part of the ridge, between {{lang|de|Riederalp}} and the glacier, was completely covered by ice. Only the summits of the {{lang|de|Bettmerhorn}}, {{lang|de|Eggishorn}} and the {{lang|de|Fusshörner}} were above the glacier. After an important retreat, the glacier again advanced 11,000 years ago during the last glacial period. The glacier reached the Rhône valley, and its ice the {{lang|de|Riederfurka}}. Remaining moraines are still visible in the Aletsch Forest.

File:Gletscherschmelze.jpg of Aletsch Glacier in the Swiss Alps (situation in 1979, 1991 and 2002), due to global warming.]]

Since the last glaciation, the glacier generally retreated. However slight climatic changes happened and, in 1860, the glacier was 3 km longer and the ice level 200 m higher.{{cite web |url=http://www.pronatura-aletsch.ch/global-warming |title=A glacier starts to melt... |publisher=Pro Natura Center Aletsch |location=Riederalp, VS, Switzerland |website=pronatura.ch |access-date=2016-03-18}}

As for many other glaciers, records show a major longer-term retreat trend.{{cite web |url=http://glaciology.ethz.ch/messnetz/glaciers/aletsch.html?locale=en |title=Grosser Aletschgletscher, Naters / Ried-Mörel (VS) |publisher=Swiss Glacier Monitoring VAW/ETHZ & EKK/SCNAT |location=Zurich, Switzerland |website=glaciology.ethz.ch |access-date=2016-03-18}}{{cite web |url=http://glaciology.ethz.ch/messnetz/lengthvariation.html |title=Glacier length variation |publisher=Swiss Glacier Monitoring VAW/ETHZ & EKK/SCNAT |location=Zurich, Switzerland |website=glaciology.ethz.ch |access-date=2016-03-18}} The Aletsch Glacier receded by {{convert|3.2|km|mi|abbr=on}} since 1870, including {{convert|1.3|km|mi|abbr=on}} since 1980. A record retreat of {{convert|114.6|m}} happened in 2006 alone.{{cite news |url=http://www.swissinfo.org/eng/front/detail/Experts_size_up_glaciers_as_they_melt_away.html?siteSect=105&sid=7930981&cKey=1184586834000&ty=st |title=Experts size up glaciers as they melt away |author=Luigi Jorio |publisher=swissinfo.ch – the international service of the Swiss Broadcasting Corporation |location=Berne, Switzerland |date=16 July 2007 |access-date=2016-03-18 |archive-date=19 December 2008 |archive-url=https://web.archive.org/web/20081219222028/http://www.swissinfo.org/eng/front/detail/Experts_size_up_glaciers_as_they_melt_away.html?siteSect=105&sid=7930981&cKey=1184586834000&ty=st |url-status=dead }}{{cite web |url=http://glaciology.ethz.ch/messnetz/glacierlist?year=2006&submit=Go!&order=desc&field=length |title=Glacier length variations of the year 2006 |publisher=Swiss Glacier Monitoring VAW/ETHZ & EKK/SCNAT |location=Zurich, Switzerland |website=glaciology.ethz.ch |access-date=2016-03-18}}

Since the end of the Little Ice Age in 1850 the glacier has lost 20 percent of its ice mass, considerably less than other glaciers in Switzerland, which have lost up to 50 percent. This is explained with the large size of the Aletsch Glacier, which reacts much slower to climate change than smaller glaciers. It is however estimated that, by 2100, the glacier will have only one tenth of its 2018 ice mass.{{cite news |last=Prantl |first=Dominik |date=11 August 2018 |title=Gletscherschmelze in den Alpen |trans-title= Glacier melting in the Alps |url=https://www.sueddeutsche.de/reise/gletscherschmelze-in-den-alpen-himmel-hilf-1.4085742 |language= de |work=Sueddeutsche Zeitung |access-date=13 August 2018 }}

Photo opportunity

On August 18, 2007, photographer Spencer Tunick used hundreds of naked people in a "living sculpture" on the Aletsch Glacier in a photo shoot which he said was intended to draw attention to global warming and the shrinking of the world's glaciers. The temperature was about 10 °C (50 °F) at the time of the photo shoot. The 600 participants on the shrinking glacier said that they had volunteered for Tunick (a collaboration with Greenpeace) to let the world know about the effects of global warming on the melting Swiss glaciers.{{cite news |url=http://www.swissinfo.org/eng/front/detail/Volunteers_strip_down_to_fight_climate_change.html?siteSect=105&sid=8116840 |title=Volunteers strip off to fight climate change |editor=swissinfo |publisher=swissinfo.ch – the international service of the Swiss Broadcasting Corporation |location=Berne, Switzerland |date=18 August 2007 |access-date=2016-03-18 |archive-date=4 May 2018 |archive-url=https://web.archive.org/web/20180504012015/http://www.swissinfo.org/eng/front/detail/Volunteers_strip_down_to_fight_climate_change.html?siteSect=105&sid=8116840 |url-status=dead }}

Notes and references

External links

[https://web.archive.org/web/20081221043237/http://www.aletschfilm.com/ Documentary film "Legacy of the Great Aletsch"]
[http://www.jungfraualetsch.ch/en/ Swiss Alps Jungfrau-Aletsch UNESCO World Heritage]
[http://www.swisseduc.ch/glaciers/alps/grosser_aletschgletscher/index-en.html Grosser Aletschgletscher on Glaciers online]
[https://web.archive.org/web/20060202232610/http://www.bettmeralp.ch/d/sommer/wanderkarte.html Panoramic drawing of area including hikes]
[http://www.gletschervergleiche.ch/default.aspx?GlacierId=56 Interactive repeat photo comparisons of the Aletsch Glacier]
[https://www.foto-webcam.eu/webcam/konkordiahuette/ Webcam overlooking Aletsch Glacier and Konkordiaplatz from Konkordia Hut]

Category:Glaciers of Valais

Category:World Heritage Sites in Switzerland

Category:Tourist attractions in Switzerland

Category:Glaciers of the Alps