A large barrier lake has formed in Nepal, with Chinese authorities warning that the lake is already overflowing and could breach as more water flows into it over the coming days.

China’s Ministry of Water Resources estimated the lake’s volume at about 2 million cubic metres as of Thursday morning. Another 3 million cubic metres of water is expected to enter the lake over the next three days, creating a high risk of a breach, China Central Television reported, according to the Global Times.

The lake has formed near the confluence of the Chhochen Khola and Purepu Tsangpo rivers in Nepal. Chinese authorities are closely monitoring its development and carrying out flood simulations to assess the possible consequences of a breach and support emergency rescue operations.

The Chotchen and Purupe rivers originate in Tibet and merge before crossing into Nepal, where the river is known as the Bhotekoshi. The Bhotekoshi is the principal upper tributary of the Trishuli river.

The warning comes a day after a sudden and powerful flood swept through areas along the Nepal-China border, killing people, destroying infrastructure and leaving hundreds missing.

The flood struck the Bhotekoshi river in Rasuwa district of Nepal on Wednesday morning. The torrent swept through the Timure and Syaphrubesi areas, damaging roads, bridges, buildings and other infrastructure before flowing downstream towards the Trishuli river.

In Nepal, rescue teams have been searching for people swept away by the flood, with bodies being recovered in several districts downstream. Authorities have also restricted movement along key highways and moved residents from vulnerable areas as they assess the risk of further flooding.

The newly formed barrier lake adds another layer of danger to an already complex rescue operation. A breach could send a sudden surge of water downstream, potentially affecting communities and infrastructure along the river system.

Chinese authorities said they would continue monitoring the lake and conducting hydrological analysis while preparing for possible emergency rescue and flood-control operations.