Kathmandu— Following a catastrophic glacier collapse in the Himalayas on Wednesday that triggered devastating flash floods and mudslides across Nepal and Tibet, a new threat has emerged: a rapidly growing barrier lake straddling the border of the two countries. The disaster has claimed 469 confirmed lives with over 1,000 people still missing as of Friday, when officials reported the newly formed lake began to overflow, temporarily halting rescue operations and raising fears of another destructive flood.

Formation of a Dangerous Lake

Scientists have identified two new lakes created by the disaster. One is located high near the glacier itself, trapping meltwater, while the more immediate concern lies with the larger lake formed on the Lhende river system in Nepal. A massive landslide caused by the glacial collapse blocked the valley, damming the river and creating a natural reservoir. Pawan Bhattarai, assistant professor at Tribhuvan University in Kathmandu, explained that the lake is an ‘avalanche-induced barrier lake,’ where ice, rock, and debris have severely constricted drainage.

Rising Water Levels and Potential Breach

Nepali authorities in Rasuwa district confirmed on Friday that the barrier lake was overflowing, causing water levels in the river to rise. Narendra Pariyar, the most senior official in Rasuwa, stated they are monitoring the situation but currently lack precise data on the lake’s size and water level. The National Disaster Risk Reduction and Management Authority (NDRRMA) has warned that a breach of the lake could trigger another flood. China has deployed an eight-member engineering team to conduct aerial surveys and 3D modelling of the area, according to state broadcaster CCTV.

Challenges in Monitoring and Mitigation

Accessing the site presents significant challenges due to the steep and isolated terrain created by the glacier collapse. Engineers noted the appearance of numerous cliffs along the lake’s perimeter, hindering access for crews and heavy machinery. Nitesh Khadka, a Nepali researcher specializing in glacial floods, explained that while preventing the natural formation of the lake is impossible, continuous monitoring, controlled breaching (if feasible), early warning systems, and timely evacuation are crucial to mitigating risk. The current estimate from China’s Ministry of Water Resources indicates the lake holds between 1.5 and 2 million cubic meters of water, with an additional 3 million cubic meters expected over the next three days – equivalent to approximately 1,200 Olympic-sized swimming pools.

Rescue efforts resumed briefly after being paused due to the overflowing lake, though remain hampered by the challenging conditions. The WHO reported damage to six health facilities and eight missing health workers. Nepal has indicated it does not currently require international assistance.

(With inputs from Al Jazeera)

Originally published on abcnews.com.np.