China, Nepal deepen weather, hydrological cooperation after mudslide

Chinese meteorological and water authorities have stepped up cooperation with Nepal following the deadly mudslide that struck the China-Nepal border, sharing monitoring data and providing weather and hydrological forecasts to support rescue efforts.

The Aug 26 disaster originated on the Nepalese side of the border and severely affected Gyirong Port in the Xizang autonomous region. The area's high altitude, complex terrain and rapidly changing weather conditions have made rescue operations particularly challenging.

"From late August to early September, plateau shear lines and low vortices are frequently active along the border, with frequent precipitation, posing serious challenges to rescue work," said Ma Xuekuan, chief forecaster at the National Meteorological Center.

Following a request from Nepal's Department of Hydrology and Meteorology around noon on Aug 26, the China Meteorological Administration organized an emergency joint consultation with its Nepalese counterpart that afternoon. A second consultation was held on Aug 31, according to Zhang Tianhang, a senior engineer at the World Meteorological Center, Beijing.

The two sides also established a WeChat working group for real-time information sharing, allowing them to respond quickly to requests during the emergency.

The consultations used MAZU, a cloud-based early warning system, to jointly assess weather conditions and forecast precipitation in the affected area.

China subsequently established a dedicated meteorological support team for Nepal and began providing daily monitoring and forecasting reports in English.

"Overall, we have provided seamless forecasting services covering the next 30 days, offering strong support for Nepal's rescue operations," Zhang said.

China has also provided Nepal with a customized version of MAZU. Nepal has since requested additional functions, including lightning monitoring, subseasonal-to-seasonal forecasts and more detailed monitoring and forecasting products.

Chinese authorities have shared a range of meteorological products and observation data through the customized version of MAZU, Zhang said.

Water authorities have also joined the effort.

A barrier lake formed near the confluence of Nepal's Cuojian River and China's Purepu Tsangpo River following the disaster. The Ministry of Water Resources immediately sent a hydrological emergency monitoring team to the area, working with Xizang's regional hydrological and water resources survey authorities.

Chinese authorities are providing Nepal with daily updates in five areas, including the development of the barrier lake; potential chain risks from impact pits along the Cuojian River; risks from glacial lakes in the Gyirong Zangbo basin; the development and risk forecasts of newly formed barrier lakes; and emergency hydrological monitoring information.

The information is intended to help Nepal assess risks and organize rescue efforts downstream, according to the ministry.

Following the disaster, the CMA mobilized resources from the national to local levels. A small ground weather station was installed near the disaster area on the night of Aug 26, and a mobile weather radar was deployed nearby on Sept 1.

"These facilities have supplemented our understanding of local weather conditions and improved the precision and accuracy of local forecasts," Ma said.