Climate change: Glacier lakes empty sooner

This is the conclusion of a new international study published on Thursday in the renowned journal Nature. To do this, researchers characterized more than 1,500 glacial lake eruptions recorded worldwide since 1900 based on water volume, peak discharge, timing and height of the source lake.

This allowed German, Swiss and Canadian scientists to estimate the development over time. Accelerated glacial melt in recent decades has led to glacial lake eruptions that are declining in volume and discharge. However, the eruptions are occurring earlier and earlier: on average ten weeks in the European Alps than 120 years ago.

Lakes at higher elevations are also affected
The scientists also found that there are now lakes with documented eruptions at higher elevations. In the Andes, Iceland and Scandinavia, they are now on average 250 to 500 meters higher than in 1900. Eruptions of glacial lakes in the European Alps found no significant differences in height in the study.

Knowing these changes is important, for example to temporarily close roads or bridges along rivers to limit damage, the researchers write in the study. Also in Switzerland there are always floods due to eruptions of glacial lakes. For example, the glacial lakes on the Plaine Morte Glacier keep authorities on their toes for years.

Especially the so-called Favergesee in the border area of ​​the cantons of Bern and Valais causes problems. In early summer, meltwater collects in a long cavity between the rocks and the ice. Once the lake reaches a critical threshold, spontaneous emptying occurs. This happens between mid-June and the end of August. Natural disaster experts have set up a surveillance system around the lake.