Water flow in the Kimrong Khola river in Kaski district has returned to normal after a landslide temporarily blocked the river, raising concerns of a possible flash flood downstream.

The river, which runs between the villages of Ghandruk and Chhomrong in Annapurna Rural Municipality, began flowing at a sharply reduced rate at around 6pm on Tuesday after the landslide blocked part of its course.

Annapurna Rural Municipality chair Bishnu Bahadur KC said the blockage gradually cleared from around midnight, allowing the river to return to its normal flow.

“The river was blocked for about three to four hours, given its size,” KC said. “The blockage began to clear from around midnight, and the water level gradually rose back to normal.”

Authorities, however, kept residents in lower-lying areas of Birethanti and Nayapul in safe locations throughout the night as a precaution.

Officials moved quickly after residents living near the Kimrong Khola reported the sudden drop in water flow on Tuesday evening. Local authorities and the district administration used public-address systems to warn communities downstream and move people to safer areas.

Workers and security personnel at the under-construction 99-megawatt Landruk hydropower project, which lies downstream where the Kimrong Khola joins the Modi river, also moved to safer locations.

Him Bahadur Gurung, ward 11 chair of the rural municipality, said yak herders in the highlands above Ghandruk had reported hearing two loud sounds that appeared to come from large masses of snow or debris falling near the river’s headwaters.

The river has caused flooding in the area before. On July 12, it was temporarily blocked and then burst through, sweeping away a suspension bridge. The floodwater flowed into the Modi river and eroded part of the Syaule Bazar section of the road linking Birethanti and Ghandruk.

Authorities remained alert overnight because of the river’s history of sudden flooding and the possibility of another blockage.