More about glacier from the Aletsch arena site (source: www.aletscharena.ch/en/world-...)
The Great Aletsch Glacier is a vision of primaeval beauty. High up on the Moosfluh, Hohfluh, Bettmerhorn and Eggishorn viewpoints is the best place to admire the scale and unique magic of the Great Aletsch Glacier. This huge river of ice that stretches over 20 km from its formation in the Jungfrau region (at 4000 m) down to the Massa Gorge, around 2500 m below, fascinates and inspires every visitor.
The Great Aletsch Glacier has shaped the landscape of the Aletsch Arena over thousands of years. During the last ice age (around 18,000 years ago), ice still covered the mountain ridges between the Bettmerhorn and the Riederhorn; only the peaks rose above the ice. How do we know? The landscape tells us: the area that was then covered by ice is smooth and rounded, but the shapes of the Bettmerhorn and Eggishorn are sharp and jagged.
We can also trace how the Great Aletsch Glacier has grown and receded in the landscape of the Aletsch Forest. Around 11,000 years ago, the terminus of the glacier was in the Rhône Valley and the glacier's edge reached almost as far as Riederfurka. The immense lateral moraine that was formed in the process is clearly visible from the moraine trail. The maximum extension of the Great Aletsch Glacier to date was around 1860. At that time, it was around 3 km longer than it is today and the edge of the glacier was a good 200 m higher, near the Aletsch Forest. This area still stands out against the surrounding countryside as a light strip of land with fairly young vegetation.
Global warming is also affecting the Aletsch Arena's "ice sea" to a concerning extent. Measurements by the Pro Natura Center Aletsch show that the Great Aletsch Glacier is experiencing dramatic ablation, shrinking by up to 50 metres in length each year and retreating significantly at the edges.
Interesting facts:
-If the ice giant were to melt, each citizen of the earth could be supplied with one litre of water a day for 3.5 years.
-The Great Aletsch Glacier has its origin in the Jungfrau region near Konkordiaplatz
-The Great Aletsch Glacier is formed by the confluence of three powerful firn streams. The Great Aletschfirn, the Jungfraufirn and the Ewigschneefeld.
-The Great Aletsch Glacier has two medial moraines. These appear as dark lines along the entire length of the ice flow.
-The medial moraine on the right in the direction of glacier flow is called Kranzbergmittelmoräne.
-The medial moraine on the left in the direction of glacier flow is called the Trugberg medial moraine.
Aletsch glacier future retreat image source: www.cambridge.org/core/journa...