'High risk' of lake breaching and causing second flood, warns China

China has warned there is a "high risk" that a lake which formed after the recent landslide near the Nepal-Tibet border may breach its banks, causing a second flood downstream.

The warning comes after Wednesday's deadly flash flood in the same area which scientists say was triggered by the collapse of a mountain glacier into a river.

As of Friday, an estimated 2.5 million cubic metres of water had accumulated at the barrier lake, according to state broadcaster CCTV. A barrier lake is a body of water formed when debris dams up a river.

Officials said that three million cubic metres of water is expected to flow into the lake between Thursday and the weekend, posing a "high risk of breach".

The area is also expected to see heavy rain in the coming days, according to state media.

The barrier lake, which formed at the confluence of the Chhochen Khola and Purepu Tsangpo rivers, had started to overflow on Thursday, according to China's Ministry of Water Resources.

Graphic showing location of new barrier lake on Nepal-Tibet border

Most of the Chinese emergency services had stopped at a village about 7km (4 mi) from Gyirong Port, the major land crossing linking Nepal and China which was hit by Wednesday's massive flood.

This was because the barrier lake at that time was "overflowing non-stop" which could lead to fresh floods or debris flows, according to a CCTV report.

But by Friday afternoon, state media reported that the "risk from the upstream barrier lake had come under control" and that rescue operations had resumed.

Authorities have sent engineering teams to monitor the lake's water levels and the atmospheric conditions, and drones have been flown in to drop off equipment and supplies.

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The lake is near the Langtang Lirung peak, where the collapsed glacier is believed to have originated, and several kilometres upstream from Gyirong Port.

Separately, Nepali authorities have warned of the risk of blockages causing further floods along the Bhote Koshi and Trishuli rivers.

They have warned people to stay away from the rivers until further notice.

Scientists have said that the flood on Wednesday was likely to have been caused by part of a glacier near Langtang Lirung collapsing into the river below, which in turn caused a massive surge downstream carrying water and debris.

Several hundred people have died in Nepal and with hundreds more still missing after the flash flood. On the Tibet side of the border alone, more than 550 are missing - nearly half of which are foreigners.