Drones helped find people after Nepal floods but the search inside hydropower tunnels is a challenge

Drone pilot Manish Maharjan has been helping Nepal's rescue effort after catastrophic Aug. 26 floods killed more than 1,000 people, using speaker-equipped drones to call out to and play music for people stranded on hillsides — a tactic that has helped locate some survivors.

The harder problem is roughly 500 workers believed trapped inside hydropower plant tunnels, which Maharjan describes as packed solid with mud 'like toothpaste in a tube,' leaving no hollow space for search equipment. At the Rasuwagadhi project, a drone reached the tunnel's end and found no sign of life.

Some workers made initial calls for help when the floods hit, but it remains unclear whether rescuers have had any contact since. About 900 workers are missing across 12 hydropower projects.

The full dispatch is available from the source below.