China and Nepal deploy joint investigation team to Nepal to determine the cause of Himalayan debris flows and floods

China and Nepal launched a joint field investigation to determine the cause of the large debris flow and flood that struck the Himalayan border area last August, causing more than 8,000 deaths and disappearances.

According to China Central Television (CCTV) and the state-run Xinhua News Agency on the 5th, Chinese experts from the geological disaster emergency scientific investigation team jointly formed by China and Nepal departed Chengdu, Sichuan Province the previous day and headed to Nepal.

The investigation team will spend about 20 days investigating how glaciers and rock collapses led to large-scale debris flows and floods in Nepal, and will also assess the risk of secondary disasters.

Professor Wang Qingshan of the Chinese Academy of Sciences and Professor Vishal Upreti of the Nepal Academy of Sciences served as co-chief scientists, and about 50 researchers from about 10 universities and research institutes, including China University of Geosciences, Nepal Academy of Sciences, Chengdu University of Science and Technology, Nanjing University, and Sichuan University, participate.

The investigation team plans to identify the process of disaster occurrence and spread through investigations linking the disaster source in Nepal, the affected areas in both countries, and downstream areas.

To this end, we plan to trace the process by which the collapse of glaciers and rocks gradually expanded into flows of soil and rocks, debris flows, and floods through drone surveys, helicopter exploration, on-site geological surveys, and sample collection.

In addition, it was decided to analyze the erosion, transport, and deposition patterns that occurred as soil and rock moved, to restore the disaster occurrence process and provide scientific basis for rebuilding the damaged area.

CCTV explained that the origin of the disaster was in Nepal, and as the damage spread beyond the border, China and Tibet became the main affected area. It is difficult to determine the full extent of the disaster through an investigation in one country alone, so tracing the origin in Nepal is a key step in uncovering the entire process.

On August 26, glaciers and rocks collapsed in the Himalayan highlands on the north-central border of Nepal, causing large-scale debris flows and flooding, resulting in the death or disappearance of more than 8,000 people in China and Nepal.

Nine Koreans, including six Doosan Energy employees and three Korea South-East Power employees who worked at the construction site of the Upper Trishuli (UT)-1 hydroelectric power plant in Nepal, are still missing.

This disaster was analyzed to have expanded into debris flows and flooding as large-scale glaciers and rocks collapsed at an altitude of 5,150m on Mount Langtang Lirung in Bagmati Province, Nepal, and poured down along the valley.

Chengdu University of Technology Vice President Hou Mingcai said, "Due to the impact of global climate change, the risk of cross-border chain disasters combining glaciers and rock collapse is increasing. Through this investigation, we will understand the change process and sediment distribution from the disaster source to the downstream and secure field data necessary for disaster prevention in the downstream area."