Seismic Linkage to Nepal Disaster; How Climate Responsible

September 1, 2026

Jayanta Basu
Seismic activity might have played a critical role in the unfolding of the major flash flood that struck Nepal’s Rasuwa district on August 26 morning killing over 900 so far. An expert has pointed out the possible climate linkage to the development, referring to an UN-led paper that is in pre-publication stage. The UN expert said that the impact on India cannot be ruled out as such flash floods are known to affect hundreds of kilometres downstream, warning that there may be “cascading effects” to follow.

Dipesh Chapagain, a senior scientist in the Global Mountain Safeguard Research (GLOMOS) programme at United Nations University Institute for Environment and Human Security (UNU-EHS), pointed out that the relationship between seismic activity and the avalanche is not yet clear. Seismic activity might have triggered the avalanche, but according to United States Geological Survey reports, it may be the other way around, with the avalanche triggering seismic activity., he said. According to Chapagain, a major part of an unnamed evolving glacier on the Nepal side of the Himalayas had collapsed, causing ice melting, which in turn blocked the river for some time and triggered the avalanche and flood.

The observation tallies with the International Centre for Integrated Mountain Development (ICIMOD) report late August 26 night. Preliminary analysis of seismic records has identified unusual signals recorded during the period of the disaster. Data from a seismometer in Jilong, approximately 12 kilometres from the affected area showed anomalous signals, while a second station in Zhangmu also recorded unusual activity … Scientists are examining whether these signals are connected to the suspected ice-rock avalanche. Chapagain, who warned of “cascading effects,” noted that another GLOF is apparently building up close to the Nepal and China border leading to the formation of another lake that may burst and trigger another spell of avalanches.

The development has also been echoed by other glacier experts from China and Nepal. He said preliminary assessment based on video footage and information from affected areas suggests that a large volume of ice and rock debris may have entered the Lhende Khola, a tributary of the Bhote Koshi river. Researchers say the event could have generated a sudden surge that carried water, sediment and large boulders downstream. The same site was devastated by last year’s Rasuwa flood is once again under threat. This was what Qianggong Zhang said who heads the climate and environmental Risks at ICIMOD. He observed that an ice avalanche in the Lhende Khola is the suspected trigger, but the cause remains unconfirmed. With a blockage still lodged upstream on the Nepal-China border, authorities warn a second flood is imminent and evacuation orders are now in place for Jilong port.

China issued a high-risk 72-hour alert warning Nepal that a newly formed transboundary barrier lake could breach, with peak water flow expected around September 1, 2026. However, the immediate risk of a catastrophic sudden breach has significantly waned as the lake has begun naturally overflowing and draining safely. Climate change, particularly rising temperature, has long been contributing to Glacial Lake Outburst Floods (GLOF). An on-going study of ours, which analysed nearly 500 GLOFs in the Hindu Kush Himalayas (HKH), shows that the rate of such incidents has risen fivefold since 1950. The HKH covers over 4.2 million square km across eight countries: Afghanistan, Pakistan, India, China, Nepal, Bhutan, Bangladesh, and Myanmar.

A marked acceleration in GLOF frequency became evident after 1950. The post-1950 average rose sharply to approximately 34 events per decade — a fivefold increase compared to the pre-1950 period,” reads the paper. Data accessed by this correspondent shows that the decadal GLOF frequency crossed 40 in recent decades. The study categorically pinpoints climatic factors as the trigger though non-climatic ones also piggyback. The observed dominance of ice avalanches (50%) and intense rainfall (25%) as primary triggers is consistent with this climate-driven pathway. The concentration of 70% of events during the summer monsoon months, when temperatures and precipitation are simultaneously at their peak, further corroborates the coupling between climatic drivers and GLOF occurrence. The predominance of moraine- and ice-dammed lakes in HKH GLOF events — accounting for around 80% of observed outbursts and almost all recorded fatalities — reflects the inherent instability of these dam types under warming conditions, it observed.

Moraine- and ice-dammed lakes are bodies of water those are being held back in mountain valleys by natural barriers made of leftover rock debris or solid glacial ice. The continuous inflow of meltwater and sediment load, amplified by increasing temperature, raises water levels which leads to an elevated hydrostatic pressure on the natural dams. This makes these dams more susceptible to breaches, which can be triggered by additional processes such as ice or snow avalanches, landslides or seismic activity. Its another well researched observation.