‘Lake Two’ Glacier Lake in Rasuwa: Current Condition and Risks

Nepalese officials, citing China’s Ministry of Water Resources, have reported that water is accumulating in the newly formed ‘Lake Two’ glacier lake in Rasuwa. According to Chinese data, this glacier lake contains approximately 650,000 cubic meters of water, as explained by Vinod Parajuli, head of the Department of Hydrology and senior hydrology expert. “This glacier lake is still filling and thus carries a risk of bursting,” he stated. Parajuli emphasized the need for heightened vigilance by rescue workers deployed in hydroelectric project tunnels in case the lake bursts. He also noted the difficulty in predicting exactly when the lake might fill completely or rupture.

Based on the lake’s location and characteristics, officials clarified that the glacier lake which burst last Sunday was located on the Nepal-China border, while the new lake lies within Nepal’s Rasuwa district. Senior hydrology expert Parajuli specified that ‘Lake Two’ is situated near the Tenzing area of Rasuwa on the western cliff of Langtang-Lirung mountain. “This lake is about one-third the size of the one that burst on Sunday. It is surrounded on three sides by rock, with one side partially open,” he said. The lake is approximately 4,000 meters above sea level, nestled within the mountainous terrain.

“This area is below where the displacement from earlier avalanches occurred but well above the river valley, meaning the lake is filling gradually rather than rapidly,” Parajuli added. Meltwater from the glacier is slowly accumulating here. The roughly circular lake covers an area of about 0.3 square kilometers; however, accurately estimating its depth remains challenging. “Since the volume of water has increased more than the surface area, depth plays an important role, and the estimated depth may be around 10 meters,” he said.

Officials noted that during the flood on September 26 (Bhadra 10), about 20 million cubic meters of water flowed down into Nepal. Compared to that, the current volume of water in ‘Lake Two’ is significantly smaller, according to chief Parajuli of the hydrology division. “However, if this lake bursts, it may trigger significant flooding downstream due to smaller landslides and accumulated sediment deposits along riverbanks,” he warned of the risks. “Therefore, most importantly, rescue personnel inside the tunnels and security forces searching for missing persons in lower areas must remain vigilant.” Should the lake burst, the likelihood of flooding extending beyond the areas damaged by the September 26 flood is low.

According to senior hydrology expert Parajuli, numerous landslides have been recorded up to 1.4 kilometers downstream since September 26. “Only the newly formed ‘Lake Two’ acts as a dam and is at risk of bursting. Further landslides are possible, and their impacts may persist,” he cautioned, highlighting the ongoing threat. Generally, as glacier lakes fill, the pressure increases the risk of rupture. “Due to leakage, some glacier lakes burst within 1-2 days. For example, the previous ‘Lake One’ burst about 24 hours after filling. ‘Lake Two’ is currently filling, so the risk of bursting is definite,” Parajuli concluded.