The Gorner Glacier is a valley glacier found on the west side of the Monte Rosa massif close to Zermatt in the canton of Valais, Switzerland. It is about long and wide. The entire glacial area of the glacier related to Gorner Glacier is , which makes it the second largest glacial system in the Alps after the Aletsch Glacier system; however it ranks only third in length behind the Aletsch and Fiescher Glacier, respectively. Numerous smaller glaciers connect with the Gorner Glacier. Its tributaries are : Gornergletscher, Monte Rosa Gletscher, Grenzgletscher, Zwillingsgletscher, Schwärzegletscher, Breithorngletscher, Triftjigletscher, and Unterer Theodulgletscher. The Grenzgletscher between the central Monte Rosa massif and the Liskamm to the south is nowadays by far the lower Gorner Glacier's main tributary. The Gorner Glacier's upper part is almost already disconnected from its lower part. Also the former tributaries Breithorngletscher, Triftjigletscher, and Unterer Theodulgletscher lost their connections to the Gorner Glacier during the last century; the Lower Theodul Glacier became disconnected in the 1980s. in front with Castor and Pollux above the Zwillingsgletscher in the back An interesting feature of this glacier is the Gornersee, an ice marginal lake at the confluence area of the Gorner- and Grenzgletscher. This lake fills every year and drains in summer, usually as a Glacial lake outburst flood. This is one of few glacial lakes in the Alps exhibiting this kind of behaviour. There are also several interesting surface features including crevasses and "table top" forms where large surface boulders have been left stranded above the glaciers surface. These tabular rocks are supported by ice that the boulder has sheltered from melting that has effected the more exposed surrounding ice. Due to the immense information about the glacier, it is perfect for a glacier project. It is the source of the riverGornera, which flows down through Zermatt itself. However, most of its water is captured by a water catchment station of the Grande Dixencehydroelectric power plant. This water then ends up in the Lac des Dix, the main reservoir of Grande Dixence. The glacier as well as the surrounding mountains can be seen from the Gornergrat, connected from Zermatt by the Gornergrat Railway.
Retreating glacier(s)
Like almost all other glaciers in the Alps, and most glaciers on the globe as well, due to global warming the Gorner Glacier is a retreating glacier—and in quite a dramatic way. Nowadays, Gorner Glacier retreats about every year, but with a record loss of in 2008. Since its last major expansion in 1859, it lost more than in distance. In these days this becomes quite obvious because the uneducated visitor usually misidentifies Gorner Glacier's main tributary as its upper part: the Grenzgletscher on the south side of the central, visible Monte Rosa massif. However, the upper Gorner Glacier traditionally is to be found on the north side. The reason is that the upper part of the Gorner Glacier is currently losing contact with its lower part and now the Grenzgletscher has become its much larger tributary. So it is easy to mismatch the Border Glacier as the upper Gorner Glacier. But this was not the case in earlier times, as the following comparison impressively shows :
