KATHMANDU — Rescue teams are trying to reach more than 900 workers believed to be trapped inside tunnels at 11 hydropower projects damaged by the catastrophic Himalayan floods.

Teams from Nepal are working with Indian and Chinese specialists to clear enormous quantities of mud, rocks and debris from tunnel entrances in the Rasuwa and Nuwakot districts. Controlled explosions and heavy excavation machinery are being used to create access routes.

The reported death toll has exceeded 900, while nearly 5,000 people remain unaccounted for. More than 10,000 people have reportedly been rescued, and over 90,000 are estimated to have been affected by the disaster.

The floods began after a glacier collapse released a destructive flow of ice, water and debris through mountain valleys. Newly formed lakes and landslide barriers continue to create a risk of secondary flooding.

Why it matters: The tunnel operation could substantially change the casualty figures. Damage to 11 hydropower facilities could also produce electricity shortages and a major financial setback for Nepal.