Chinese scientists have developed a cross-border early warning system with counterparts in Nepal to monitor Himalayan glacial lake outburst floods. The system has issued timely alerts over the past several years, effectively preventing casualties. But on Wednesday, a high-altitude ice-rock avalanche took everyone by surprise. The debris flow hit a river in Nepal, generating a devastating flash flood that swept all the way down to Gyirong county in the Tibet autonomous region in China. Some...