BIDUR, Nepal — Rajendra Dawadi was inside his classroom when a colleague rushed in with a warning: Floodwaters were racing through Nepal’s Trishuli Valley, tearing apart homes, bridges and entire villages. Then a teacher received another warning by phone. Moments later, a parent arrived to take her child home. The danger had not yet been confirmed, but Dawadi, the principal, had little time to act. He rang the school bell and ordered his students and staff out of the building and toward higher ground. “I immediately decided to stop ... school" and get the children out, he told The Associated Press. As he followed them to a nearby hill, the floodwaters rose behind him. From the safety of the hillside, he turned to watch the school where he had once been a student — and where he had spent years teaching — disappear beneath a torrent of water, mud, boulders and debris. Two staff members could not make it and remain missing. Dawadi’s decision to evacuate the school saved at least 900 students from last week’s devastating flash floods in Nepal, unleashed after a glacial collapse