Danger from the glacial lake: Juneau under water – what now?

Danger from the glacial lake: Juneau under water – what now?

On August 1, 2024, there was a disaster alert in Juneau, USA. The reason was a massive flood caused by the sudden emptying of a glacial lake. According to the University of Potsdam The rising Mendenhall River led to the destruction of hundreds of homes in the city. This event highlights the dangers posed by glacial lake outbursts worldwide, particularly when human settlements are located in the direction of the river.

A prominent example is Suicide Lake above Juneau, which drains regularly. Research in this area has intensified to better understand the causes and consequences of such outbreaks. In early summer 2023, researchers traveled to Alaska to survey Desolation Lake. The lake, which has an area of ​​12 square kilometers and stores approximately 500 million cubic meters of water, is of significant importance as it has erupted at least 48 times since 1972, transporting large amounts of sediment during each event.

Research under extreme conditions

The ones from the Potsdam Institute for Climate Impact Research (PIK) Supported study, published February 16, 2023 in the journal Nature, analyzed glacial lake eruptions worldwide since 1900. It showed that these eruptions occur earlier in the year and from higher altitudes due to global warming, but have become smaller overall. For example, glacial lakes in high mountains in Asia are now breaking up about 11 weeks earlier than they did over 120 years ago. In the European Alps even 10 weeks, while northwestern North America is affected 7 weeks earlier.

Research at Desolation Lake led to further interesting findings. Natalie Lützow, who is doing her doctorate on the lake, found that the amount of water tripled during the eruptions. The Lituya Glacier, which impounds this lake, has also been extensively studied to understand the influence of climate change on the stability of the glacial lake environment.

The dangers of glacial lakes

Despite the research, there is no clear evidence that the dangers of glacial lake outbursts are increasing due to climate change. Many glacial lakes were examined and exciting data was collected. Remote sensing plays a central role in observing and monitoring these dangerous waters. The geological conditions in mountains, such as the Alps, also show how various factors such as small earthquakes, extreme weather events and temperature fluctuations can endanger stability.

The need to establish early warning systems for settlements downstream became increasingly urgent. Glacier retreat in regions such as the European Alps and Scandinavia could result in these areas becoming largely ice-free by the end of the 21st century, while mountainous regions in Patagonia and Alaska are expected to retain larger glaciers beyond the year 2100.

The comprehensive analysis of over 1,700 documented glacial lake eruptions makes it clear how closely climate change, glacier retreat and natural hazards are linked. The future of glacial lakes remains uncertain, and research will be crucial to understanding the impact of climatic changes.