Kathmandu: The devastating flood that struck the Lhende River on the Nepal-China border in Rasuwa last Tuesday was caused by the eruption of a supraglacial lake, the Department of Hydrology and Meteorology has confirmed. The flood has left 19 people missing (both from Nepal and China), claimed seven lives, and caused severe damage, including the destruction of a 30-megawatt hydropower project, the Miteri Bridge, and the loss of over 100 electric vehicles, halting trade with China.

According to flood expert Binod Parajuli, satellite analysis shows that a glacial lake, once spread over 0.75 square kilometers at an elevation of 5,150 meters in the upper watershed of the Lhende River, shrank to 0.60 square kilometers after the outburst, confirming a large volume of water had been released downstream.

The International Centre for Integrated Mountain Development (ICIMOD) also verified the cause, stating that a newly formed supraglacial lake triggered the flood. This is the second such incident in Nepal in recent weeks, following a similar glacial lake outburst in Thame, Solukhumbu, increasing alarm over frequent glacial disasters.

Climate and glacial experts have warned that climate change is fueling a chain reaction of glacier melting and lake formation, which could cause more frequent and severe flooding in the Himalayan region. Dr. Maheshwar Dhakal, Head of the Climate Management Division at the Ministry of Forests and Environment, said, “The greatest damage from these events is felt in downstream areas, and a robust early warning system is urgently needed.”

According to glacial lake expert Sharad Prasad Joshi, mapping, monitoring, and updating the list of dangerous glacial lakes is essential. ICIMOD's research notes that floods triggered by glacial lakes now carry more gravel, sand, and debris, making them far more destructive.

Worsening Climate Indicators
The World Meteorological Organization’s 2024 Climate Status Report declared 2024 as the hottest year on record, with the global average temperature rising by 1.54°C compared to pre-industrial levels. Of that, 1.3°C is human-induced. Sea levels have also risen, and glaciers lost an average 1.2 meters of ice thickness in 2023.

ICIMOD data indicates that glacier melt in the Hindu Kush Himalaya increased by 65% between 2011 and 2020 compared to the previous decade. What was previously a once-in-a-decade glacial disaster is now occurring multiple times a year. In just May and June 2025, glacial lake floods occurred in Nepal (Humla, Rasuwa, Mustang), Afghanistan (Andorab), and Pakistan (Chitral/Hunza).

Despite this growing threat, Nepal currently has early warning systems only for Imja and Tsho-Rolpa lakes. ICIMOD experts, like Chango Zhang, highlight the lack of sufficient technology and data infrastructure to monitor the rapidly changing high-altitude environment.

Nepal Secures Climate Fund Support
In response, Nepal has secured a Rs 5 billion grant from the Green Climate Fund (GCF) to reduce the risk of four high-risk glacial lakes. The project titled “Protecting property and people from the risk of climate-induced landslides and glacial lake outburst floods in Himalayan watersheds” was approved at the 42nd GCF Board meeting in Papua New Guinea. An additional Rs 2 billion in co-financing will come from the Government of Nepal, UNDP, and independent power producers.

Nepal previously lowered the water level of Imja Lake by 3.4 meters, showcasing successful mitigation. A joint ICIMOD-UNDP report warns that 47 glacial lakes across Nepal, China, and India are at high risk, with 21 in Nepal alone. The potential damages could reach billions of dollars and significant human losses if left unaddressed.

International Advocacy for Mountain Nations
Nepal continues to push for global climate justice. At the Sagarmatha Dialogue held in early Jestha, Nepal emphasized the disproportionate impact of climate change on mountainous nations, despite their minimal contribution to the crisis. Dr. Dhakal emphasized how upland-lowland linkages must be addressed in climate policy, while Professor Rajesh Kumar Rai called attention to the growing strain on Himalayan economies.

The urgency is clear: without early action, mapping, and climate finance, the glacial flood crisis in the Himalayas is only set to worsen.