Kathmandu, Aug. 29 -- Deep beneath the mud and debris of Nepal's Trishuli corridor, hundreds of hydropower workers are believed to be trapped in tunnels and underground powerhouses.

Three days after Wednesday's catastrophic flood, rescuers are still struggling to reach some of them. Roads and bridges have been swept away, tunnel entrances buried and, in some cases, authorities do not know exactly where the workers are.

A video circulating widely on social media and in Nepali media offers a glimpse of one such rescue. It shows Nepali Army soldiers working through thick, frozen mud inside a tunnel, with one soldier pulling a trapped worker while another pushes him from behind.

The footage, filmed during the rescue of workers at the 216-m...