Kathmandu, Aug. 31 -- Roshan Kumar Joshi, an environmental expert from Morang who worked on the Upper Trishuli-1 Hydropower Project under a Korean company, has been out of contact since last week's devastating floods in central Nepal. Joshi's relatives have scoured social media for videos, photographs and maps that might offer a clue to his whereabouts. They have also inquired with other company employees.

"One of the colleagues who reportedly talked to him for the last time said she heard him sending his colleagues outside, shouting, 'Run, run quickly,'" one of Joshi's relatives said. "We have no idea what happened after that."

On Saturday, Joshi's relatives asked police authorities to trace the last location of his mobile phone. The r...