165 Dead After Himalayan Flood as Scientists Warn Climate Change May Be Destabilising the Mountains

Scientists say climate change likely contributed to the Himalayan flood that killed 165. The disaster may have been triggered by an ice-rock avalanche.

This week's devastating flood along the Nepal-Tibet border, which has claimed 165 lives, bears the fingerprints of climate change, scientists have warned. The disaster unfolded when a massive wall of mud and rock collapsed into a Himalayan river, unleashing catastrophic floods that swept through towns and valleys.

Authorities said on Thursday that at least 800 foreigners are among the nearly 1,500 people still unaccounted for.

Rising temperatures and melting glaciers probably played a role

"Climate change is generating conditions that can destabilise high-mountain rock and ice," said Simon Cox, chief scientist at the Mountains to Sea programme at Earth Sciences New Zealand. According to Cox, such destabilisation makes collapses and cascading hazards more frequent.

While investigators are still working to pinpoint the exact cause of Wednesday's disaster, scientists suspect it began with a massive ice-rock avalanche on the northern slopes of Nepal's Langtang Lirung peak. The debris plunged into the Lhende Khola river on the Tibetan side, setting off a chain of events that crossed borders.

The multi-stage hazard chain damaged at least six major hydropower plants and infrastructure at the Gyirong Port trade hub. The impact was felt more than 100 kilometres downstream, near the Indian border, where river channels were altered.

Experts caution against blaming climate change as the sole trigger. However, they acknowledge that rising temperatures and melting glaciers likely contributed. Warming reduces ice support on steep slopes, increases meltwater, and alters freezing, thawing, and rainfall patterns, all of which can weaken mountainsides.

Similar but smaller-scale surges have hit the region in recent years. These include a 2025 flood at Gyirong, a glacial lake outburst in Thame in 2024, and another in Sikkim in 2023.

Across the Hindu Kush mountain range, floods, landslides, avalanches, and droughts are becoming more frequent and intense. The Nepal-based International Centre for Integrated Mountain Development has warned that these changes pose a growing threat to regional populations.

Farooq Azam, senior cryosphere specialist at ICIMOD, said rising mountain temperatures have made the ice-clad parts of the earth's surface far more vulnerable. He believes heavy snow melt, combined with seismic activity, probably triggered the initial rock and ice avalanche.

The long-term trend is alarming. In 2023, the United Nations reported that global warming had caused Nepal's mountains to lose nearly one-third of their ice cover in just over 30 years. Glaciers in Nepal melted 65% faster in the decade leading up to that report than in the previous decade.

Benjamin Horton, dean of the School of Energy and Environment at the City University of Hong Kong, described Wednesday's disaster as a potential "compound event." This occurs when an earthquake interacts with climate-driven changes, such as glacier loss, thawing permafrost, and slope instability, to produce a more complex and destructive outcome.

Understanding these cascading risks is critical for building resilience in high mountain regions, Horton added.