Himalayan Glacial Floods: A Sign of Climate-Driven Disasters

When a torrent of water, rocks, and mud swept through her remote Nepali village last week, Pema Tamang and her neighbours sought refuge in a Buddhist shrine that had been rebuilt just a year after the 2015 earthquake. The shrine, which had been destroyed in the quake, became their lifeline. "We were able to rebuild the stupa only last year... Sheltering in it was how we saved our lives from the floods," Tamang said from a makeshift shelter in Kathmandu.

The August 26 floods in Nepal and neighbouring China have killed over 1,000 people, with thousands still missing, including many feared trapped in tunnels at hydropower projects. The disaster was triggered when a collapse of bedrock and glacier ice sent a surge of debris and water down several Himalayan rivers.

While scientists caution against directly attributing this single event to global warming, the broader trend is clear: the Himalayas are warming faster than many other regions, increasing the likelihood of such complex disasters. Saswata Sanyal, a disaster risk resilience expert at the International Centre for Integrated Mountain Development, noted that climate change is playing a significant role in the Hindu Kush Himalayas, causing cascading hazards that hit downstream communities and infrastructure.

Warmer temperatures are accelerating ice melt, leading to more rockslides, avalanches, and flash floods. An avalanche can dam a river, only to release a sudden flood when the dam breaks. Heavy rainfall after an initial disaster can compound the destruction. Last year, flash floods in the same region of Nepal killed nine people and caused millions in damage. Over the past decade, events like the 2013 Kedarnath floods, the 2021 Chamoli disaster, and the 2023 South Lhonak glacial lake outburst have killed thousands and caused hundreds of billions of dollars in damage.

People in Nepal were still recovering from last year's floods, Sanyal said, "and before they could fully adapt, the next one came." The Hindu Kush Himalaya, which stretches across eight countries and contains the largest ice mass outside the polar regions, supports nearly 2 billion people through its river systems. Glacier ice loss has accelerated sharply since 2000, and thawing permafrost is further weakening mountain slopes.

Satellite imagery of the recent glacial collapse shows a massive block of bedrock and ice plunging into a valley, sending a wall of water and mud several stories high through communities downstream. In some areas, the danger may become so severe that rebuilding is no longer viable, forcing residents to relocate. Manjeet Dhakal, a Nepali climate policy expert and UN climate negotiator, said the "adaptation threshold has been crossed in some areas." Unlike an earthquake, which may leave belongings recoverable, a catastrophic flood can wipe out the land itself, along with roads, water systems, schools, and electricity.

Mitigation measures include stricter land-use rules, better infrastructure assessments, cross-border monitoring, and early warning systems. However, of the 670,000 people who received text alerts about the floods, some were visitors or migrant workers who could not understand Nepali, while others downplayed the risk. Chanda Lal Chitrakar, a 62-year-old from Nuwakot, admitted he paid little attention to the warnings and only ran uphill when the waters rose. Sanyal stressed that warnings need to include clearer instructions on what actions to take, and that development should be prioritised in safer areas, with infrastructure assessed for multiple hazards and Indigenous knowledge incorporated into planning.

Dhakal noted that Nepal has contributed less than 0.1% of global greenhouse gas emissions, yet bears some of the severest impacts. "We should blame those who are responsible for increasing the global temperature, those who have benefited from the fossil fuel economy for such a long time," he said. "We can at least use this devastating example as an inspiration to urgently reduce carbon emissions."