A large natural lake formed near the confluence of the Chochhen Khola and Purepu Sangpo rivers in Nepal’s Rasuwa district has breached, raising fears of another sudden surge in the Bhotekoshi River. Rasuwa Chief District Officer Narendra Pariyar confirmed the development on Friday, citing the Nepali Army. The lake is located near the Nepal-China border.

Chinese authorities had warned on Thursday that water was overflowing from the lake and that it could collapse at any time. Nepal’s disaster management authority said water levels in the Bhotekoshi River had risen. Helicopters stationed in Dhunche and Rasuwa were being prepared for an aerial survey of the river and surrounding areas.

China’s Ministry of Water Resources estimated that the lake held about 2 million cubic metres of water on Thursday morning, with a further 3 million cubic metres expected to enter over the following three days. Flooding on Wednesday damaged roads, bridges and other structures in Timure and Syafrubesi, while many people remain missing. Authorities have not yet confirmed how much water was released by the breach.