Aletsch Glacier

The Aletsch Glacier is the largest glacier in the Alps.

It is located in the eastern Bernese Alps within the Swiss canton of Valais. This massive ice body covers a huge area of the landscape. Because of its importance, the area is a UNESCO World Heritage Site. This status helps protect the glacier and the surrounding environment.

The glacier is a vital part of the largest glaciated area in western Eurasia.

Glaciers form through a process of accumulation and compaction. It begins when snow falls and stays on the mountainside. When the amount of snow and ice accumulation exceeds the amount that melts, the ice grows. As layers of snow build up, they create immense pressure. This pressure packs the snow into thick, dense ice. Eventually, the weight of this ice causes it to move. A combination of gravity and the pressure from overlying snow makes the ice flow downward.

The Aletsch Glacier is not one single block of ice. Instead, it is formed by four smaller glaciers that converge at a place called Konkordiaplatz.

One major part is the Jungfraufirn, which is known as the "Eternal snow field." Another is the Fiescher Glacier, which is long and about 500 meters wide on average. The third is the Grosser Aletsch Glacier, which flows from the northwest. The fourth is the smaller Ewigschneefeld. At the meeting point of Konkordiaplatz, the ice is incredibly thick. It can reach a maximum thickness of 900 meters.

As the ice moves toward the valley, its shape and thickness change. After passing Konkordiaplatz, the glacier flows toward the southeast. It moves at a rate of about 180 meters per year. The glacier is about 1.5 kilometers wide in this section. As it moves down the valley, much of the ice melts. The thickness decreases from 900 meters to around 150 meters. The glacier also carries dark debris called moraines. These medial moraines are bands of rock and dirt located in the middle of the ice. The westernmost band is named the Grosser Aletsch Moraine. The easternmost is the Fiescher Moraine.

History shows that the Aletsch Glacier has changed significantly over time. It is currently a retreating glacier, meaning it is getting smaller. During the last glacial periods, the glacier was much larger. About 18,000 years ago, it covered the lower part of the ridge. It advanced again 11,000 years ago and reached the Rhône valley. Since the end of the Little Ice Age in 1850, the glacier has lost 20 percent of its ice mass.

Since 1870, it has lost a large amount of its length and thickness. In 2006, the glacier experienced a record retreat. Scientists estimate that by the year 2100, it may have only one-tenth of its 2018 ice mass.

Despite its retreat, the glacier remains a major part of the local ecosystem and economy. The melting ice provides water for the Massa stream. This stream flows through the Massa Canyon and is used to generate hydroelectric power.

The area is also a destination for tourism. People use cable cars to reach high viewpoints. There is even a railway station at 3,450 meters that provides access to the upper glacier. Hikers can use a suspension bridge built in 2008 to cross the river. This allows people to walk between different parts of the glacier.

The glacier is also a site for environmental awareness. In 2007, a photographer named Spencer Tunick organized a large event on the ice. He used 600 participants to create a "living sculpture." This event was intended to draw attention to global warming and the shrinking glaciers. The Villa Cassel, located at 2,065 meters, now serves as a center for the organization Pro Natura. It hosts exhibitions about the site to help people understand the changing environment.