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

Not even the world’s fastest sprinters could have outrun the devastating floodwaters that struck a border crossing between China and Nepal last week, according to one of the first peer-reviewed assessments of the disaster.

Researchers from the Chinese Academy of Sciences (CAS) calculated that the surface velocity of the debris flow was 19 metres per second (62 feet per second) when it struck the checkpoint at Gyirong Port in Tibet.

This is almost twice Usain Bolt’s average speed when he set the...