Inland “tsunamis” pose a danger to people and disrupt infrastructure due to lakes formed by melting glaciers overflowing their banks.
Glaciers around the world are melting at an alarming rate, creating massive lakes. Meltwater fills the depressions left by glaciers, forming glacial lakes. As temperatures rise and more glaciers melt, the water levels in these lakes rise, threatening communities living downstream. If the lake water rises too high or the surrounding land erodes, the lake can overflow, sending water and debris rushing down the mountainside.
Dig Tsho Lake in the Langmoche Valley, Khumbu Himal, Nepal. (Photo: Matthew Westoby/Springer Nature).
This phenomenon is known as glacial lake outburst. According to research published on February 7 in the journal Nature Communications, approximately 15 million people worldwide live within 48 kilometers of glaciers that may be at risk. More than half of these individuals are concentrated in four countries: India, Pakistan, Peru, and China. This is the first study to specifically examine the potential impacts of glacial lake outbursts.
Tom Robinson, a lecturer at the University of Canterbury in New Zealand and co-author of the study, likens glacial lake outbursts to “inland tsunamis.” He compares its impact to a sudden dam failure. “For example, if the Hoover Dam were suddenly removed, you would have a large lake behind it. Water would need a place to go. It would rush down the valley, creating massive flood waves,” Robinson explains.
Such floods can occur with little or no warning. Previous glacial lake outbursts have killed thousands and destroyed many homes and critical infrastructure. The Cordillera Blanca mountain range in Peru is a hotspot for this dangerous phenomenon. Since 1941, the range has experienced over 30 glacier-related disasters, from landslides to glacial lake outbursts, claiming the lives of more than 15,000 people.
While researchers are unsure how much last year’s flooding in Pakistan was related to melting glaciers, the country has more glaciers than any other location in the world outside of polar regions. In 2022 alone, there were at least 16 glacial lake outburst incidents in the Gilgit-Baltistan region of northern Pakistan, far exceeding the 5-6 incidents reported in previous years. The study found that the most vulnerable area for glacial lake outbursts is the high mountain region of Asia, including Nepal, Pakistan, and Kazakhstan. On average, individuals in this region live within 9.7 kilometers of glacial lakes.
According to Robinson, the Andes mountains, including Peru and Bolivia, are among the most concerning areas, due to the lack of research conducted in the region. The research team emphasizes that over the past two decades, glaciers in the Andes have been melting faster due to climate change, creating large glacial lakes and increasing the flood threat from outbursts. North America and the European Alps are not high-risk areas due to fewer people living near glacial lakes.
The melting of glaciers is one of the most apparent and visible signs of the climate crisis. A recent study by David Rounce, a glaciologist at Carnegie Mellon University, found that half of the world’s glaciers could disappear by the end of the century, even if global efforts to combat climate change, such as phasing out fossil fuels, are successful. With temperatures continuing to rise, Robinson hopes that his research and that of his colleagues can help global leaders identify which countries need early warning systems for flooding caused by melting glaciers.
