Authorities rescued 96 people including nine foreigners after a landslide on Sunday in Gorkha district, about 100km west of Kathmandu, blocked the Budhi Gandaki River, leading to downstream flooding.
The river is a tributary of the Trishuli River, downstream from another tributary where a glacier collapse caused a catastrophic flood in August that killed 1457 people, with thousands still missing.
The army said the latest rescue operation was continuing on Monday even as the flood has receded.
There were no reports of fatalities, but five villagers are out of contact after the flooded river carrying black muddy sludge and debris washed away homes and damaged infrastructure including three hydroelectric plants, national disaster authorities said.
Bhuwan Raj Ojha, an official of the Manaslu Conservation Area Project (MACP) that includes a popular trekking route, said there were more than 100 foreign trekkers stranded in different areas who could not return because part of the trail had been swept away.
"Those hikers who want to return because of the flood need to be rescued. Those who want to continue their trekking can do so from locations that are safe," Ojha told Reuters from Gorkha.
"There are restaurants and tea houses along the route. They are safe."
The International Centre for Integrated Mountain Development said the latest flood may have been triggered by the failure of a temporary river blockage created by a landslide, according to preliminary accounts from Nepal's authorities reviewed by ICIMOD.
"This event is another reminder of how exposed mountain communities and river corridors remain to sudden, cascading hazards," Pema Gyamtsho, director general of ICIMOD, said.
"While response efforts must remain the immediate priority, understanding what triggered this flood will be critical for reducing future risks and strengthening resilience."
