China-Nepal floods: first research shows that no one could have outrun debris flow

In a recent study, researchers from the Chinese Academy of Sciences (CAS) revealed that no one could have outpaced the destructive floodwaters that ravaged a border crossing between China and Nepal. The CAS team determined that the debris flow's surface velocity at Gyirong Port in Tibet reached 19 meters per second, nearly twice the average speed of Usain Bolt during his world-record-breaking 100 meters sprint in 2009 and 50% faster than his top speed.

This devastating event was triggered by the collapse of a high-altitude glacier in Nepal, resulting in an ice avalanche, debris flow, mudslide, and ultimately a flood. The Chinese researchers used digital models and frame-by-frame analysis to reconstruct the disaster, emphasizing the limited response time and the need for rapid identification, information transmission, and emergency decision-making.

The floods claimed at least 16 lives in China, with another 546 missing, while Nepal suffered 1,058 deaths and 4,606 people still unaccounted for. The research highlighted the challenges in detecting and monitoring high-altitude ice avalanches, suggesting potential solutions like tracking the flow's route, improving monitoring points, using multiple data sources, and considering temporary dams' benefits for evacuation efforts.