Global Warming

Glaciers Are Bursting, Causing Deadly Floods

Central Asia’s glaciers make up the third-largest mass of frozen fresh water on earth, the planet’s “third pole,” The region’s thousands of glaciers and regular snow melt form the headwaters for 10 of Asia’s biggest rivers, which bring drinking water, power and irrigation directly to 210 million people, while these river basins indirectly support more than 1.3 billion people.

That resource is now doubling as a hazard, with glaciers skipping the melting process altogether to rupture and flood in a region that has warmed at twice the global rate of climate change.

Last week, a glacier in northeastern Afghanistan burst and flooded the Panjshir River basin, killing at least ten people. The floodwater triggered landslides as it carved through the valley and damaged 56 houses, washed out two bridges, wrecked a highway, broke an irrigation canal, and swamped farmland.

That same week, a glacier in western China released 35 million cubic meters—or 14,000 Olympic swimming pools—of fresh water into the Yarkant River basin, prompting evacuations.

As glaciers heat up, meltwater can pool into lakes at their feet. The resulting glacial lakes sit behind walls of ice and debris collected by the glacier’s downhill slide called terminal moraines. These natural dams can break due to any number of environmental triggers, including rainfall. In the Panjshir flood, an icecap melted, reportedly triggering a small landslide, which then in turn caused a glacial flood.

Glacial lakes are more likely to form if the glaciers they are under intense heat, which is now very common amid global deglaciation. Different altitudes of the Yarkant River Basin have warmed between 2°C and 3.5°C since 1961. These kinds of floods are increasing in frequency and tend to occur at lower altitudes, where glaciers often sit closer to civilization.