Nepal flood disaster sparks concern over glacier-related events amid climate change
More landslides have been occurring in regions with glaciers, experts said.
While the exact cause of the recent massive landslide that triggered a catastrophic flood in Nepal remains unknown, the event is prompting worldwide discussion from some experts about how human-amplified climate change is affecting glaciers.
The deadly Aug. 26 flood was triggered by a landslide that occurred about 12 miles northeast of the Rasuwagadhi border post along the Nepal-China border, according to Nepal Disaster Management. The landslide took away a large chunk of land, which prompted the collapse of at least part of a glacier on the mountainside, Göran Ekström at the Lamont-Doherty Earth Observatory at Columbia University told ABC News.
But climate change's role in melting the glacier and causing the catastrophe is unclear. To make that determination, scientists would have to assess whether the saturation of water in the mountain's bedrock caused the landslide, which could have come from glacial or permafrost melt within the rock, Richard Alley, a glaciologist at The Pennsylvania State University, told ABC News.
Yet, experts told ABC News the event, which has killed over 1,000 and left over 4,000 missing as of Tuesday, is a reminder of the importance of monitoring and studying glaciers worldwide as the impacts of glacier change are increasingly affected by climate change.
In general, more landslides have been occurring worldwide in regions with glaciers -- many of the same regions where permafrost in mountainsides is melting, Anders Anker Bjørk, associate professor of geography at the University of Copenhagen, told ABC News.
"This frost is melting, making the mountains more unstable," Bjørk said. "At the same time, we're also seeing glaciers that are retreating, and that's exposing new mountainside, which can also be more unstable than a mountain which has been there for a really long time."
Many glaciers that have the potential to collapse do not lie above or near heavily populated areas, and therefore do not have as much destructive capability as what was seen in Nepal, experts said.
"These things have the potential to happen anywhere where there are glaciers, but they are particularly a problem in high relief areas and in mountains that are perhaps susceptible to earthquakes and have a lot of kind of weak bedrock," Brenda Hall, a glaciologist at the University of Maine, told ABC News.
While any formal attribution of this specific collapse to climate change is premature, the collapse happened on a mountain that warmed rapidly for decades after four consecutive summers that all rank among the five warmest in that last 86 years, Zeke Hausfather, a climate scientist at the University of California Berkeley, wrote in a Substack post for "The Climate Brink."
"A rapidly warming climate and retreating glaciers are increasing risks of these sorts of events in the region, whether or not we can ultimately attribute this particular event," Hausfather wrote.
Disasters similar to what occurred in Nepal, especially those known as "glacial lake outbursts," are becoming more frequent, Hall said.
Glacial lake outbursts, which are not what occurred on the Nepal-China border, refer to the bursting of large lakes formed by glacial meltwater, which are often held in place by unstable dams and can cause floods, particularly in areas with steep terrain, experts said.
"This may have been, you know, a slightly different form of glacial hazard, but they're all sort of part of the same problem in that as glaciers are melting more, they're becoming more unstable, and that's just leading to, you know, more potential for problems with them," Hall said.
Worldwide, an estimated 15 million people could be exposed to impacts from potential flooding from glacial lake outbursts, with more than half of the globally exposed population found in just four countries: India, Pakistan, Peru, and China, according to a Nature Communications study.
The impacts of human-amplified climate change gradually intensify and unfold over long periods of time, which differs from effects from short-term seasonal changes, experts said.
Even fairly small changes in climate can make formerly rare or never-seen events become notably more common, such as intense flooding or rising sea levels, according to Alley.
Seasonal melting that is typical in glaciers could also have triggered the landslide, if glacial or permafrost melt was the ultimate cause of the event, Kristen Cook at the Université Grenoble Alpes in France told ABC News.
Mohan Bahadur Chand, a glaciologist at Kathmandu University in Nepal, told ABC News that the cliff that broke off the mountain that caused the landslide in Nepal "was not hanging like that" about 20 or 30 years ago. Chand attributed the visible change in the mountainside to glacial melting.
"Once it's hanging, it's difficult to stabilize like that at the top of the cliffs at very high slopes," Chand said.
In addition to regions in South Asia, experts said the Andes Mountains in South America stand out as at risk for similar events involving landslides and glacier collapses in the future.
Last year, a similar event occurred at the Tracy Arm Fjord in southeastern Alaska, where a mountain formation fell into the water on Aug. 10, 2025. The collapse was so forceful that it created the world's second-highest tsunami ever recorded. A recent analysis found the event, or at least the scale of it, was attributable to glacial retreat that changed the landscape of the area.
No one was harmed in the event.
An incident of the massive scale seen in Nepal is rare, but smaller, similar disasters will be more frequent in the future as the melting of glaciers and permafrost creates unstable bedrock in mountains, according to Cook.