As hundreds of rescue workers scoured muck-filled ravines and valleys on Tuesday looking for survivors after the sudden collapse of a Himalayan glacier, distraught relatives gathered at the disaster site to search for family members, almost resigned to the likelihood they were dead.

Rescuers in northern India were working Monday to rescue more than three dozen power plant workers trapped in a tunnel after part of a Himalayan glacier broke off and sent a wall of water and debris rushing down the mountain in a disaster that has left 18 people dead and 165 missing.