A major river in Nepal has flooded, sweeping away houses, bridges and damaging a part of hydropower station, authorities have said.

Officials say they have rescued 95 people, including nine foreigners, along the bank of the Budhi Gandaki River in the central Gorkha district, the army confirmed. No casualties have been reported yet, however five people are missing.

A video of the flood shows the moment raging waters sweep down a valley and wash away an entire building complex.

Nepal is on high alert and still trying to recover from catastrophic floods that hit its border towns with Tibet two months ago, leaving more than 1,400 people dead and thousands missing.

Sunday’s flood tore through the Gorkha district as children and communities prepared to mark the first day of the Dashain festival, a major moment in the Nepali calendar.

More than 200 homes were damaged and more than 650 people were impacted by the flood, Nepal’s Disaster Risk Reduction and Management Authority said.

Some settlements have been completely cut off and are now only accessible by air, a local official told The Kathmandu Post.

Nepal’s army said it had mobilised four helicopters for search and rescue operations.

Families have been forced to flee their homes, with many facing uncertainty over where they will find safe shelter and access to essential supplies.

Ganesh Karki, a resident of Jagatbagar, told The Kathmandu Post that he and others took shelter about 500m (0.3 miles) uphill in a nearby forest after receiving a warning call about the flood early in the morning.

“We never imagined a flood of this size,” he said. “The water surged for about 15 minutes and then stopped repeatedly throughout the morning. We are afraid to return home at night.”

The flood swept away about a dozen houses and several suspension bridges, while a hydroelectric project was damaged, carrying some of the construction equipment away, the disaster management authority said.

Within a couple of hours, the river’s water levels at one location had risen from two metres (6ft 5in) to nearly 8.5m (27ft 9in), officials said.

Binod Parajuli, a meteorologist who works with the Nepalese government, said: “Our hydrological station was swept away and we are not getting any data from that location.”

However, experts say the debris-flow is much smaller and travelled more slowly than the devastating flash floods in August.

What caused the latest flood is still unclear. Some say a landslide may have blocked the river or its tributary for some time, causing the dammed water to burst out, while others say locals upstream saw an ice-avalanche.

Save the Children is mobilising an emergency team to respond to Sunday’s flood.

“Children’s lives have been ripped apart in an instant yet again”, the charity’s director in Nepal, Tara Chettry, said.

“We are yet to see the full scale of the damage, but they may have lost their homes, schools and communities. Many children in Gorkha will still be in shock and distress after the mega floods in August, barely having a chance to get back on their feet.”

The Budhi Gandaki is a tributary of the Trishuli river, downstream from another tributary where a glacier collapse caused the previous disaster.

Nepal is prone to disasters, from earthquakes to landslides and floods, as a result of the unpredictable natural environment in the Himalayas. Hundreds of people were killed in August after floods tore through villages along the Nepal-Tibet border. That disaster was caused by an avalanche of rock and ice near the peak of Lantang Lirung, a mountain on Nepal’s side of the Himalayas.

Experts say climate change, which is making glaciers melt faster, is likely raising the risk of such disasters, leaving local communities increasingly vulnerable.