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 morning, 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 barrier lake, which formed at the confluence of the Chhochen Khola and Purepu Tsangpo rivers, has already started to overflow, according to China's Ministry of Water Resources. The area has also seen heavy rain.Authorities have sent engineering teams to monitor the lake's water levels and the atmospheric conditions.A CCTV report on Friday morning said that most of the Chinese emergency services were stuck at a village about 7km (4 miles) 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 was "overflowing non-stop" which could lead to fresh floods or debris flows. Due to the risks, search and rescue operations had to be suspended near the Nepal-Tibet border, according to the report.