By The South Asia Times

KATHMANDU, Nepal – A catastrophic flash flood that tore through Nepal's Bhotekoshi River on Wednesday has killed at least 162 people, with 826 others - including foreign tourists - still missing, according to the Disaster Management Authority.  

Security officials and disaster experts say the disaster may rank among the deadliest in Nepal's modern history.

The mid-morning flood, triggered by an avalanche that blocked a tributary on the Chinese side of the border, unleashed a wall of water that swept through settlements and trekking routes across three districts, causing widespread devastation.

The flood originated after an avalanche blocked the flow of the Lhende tributary of the Bhotekoshi River, first striking Timure near the Nepal-China border at Rasuwagadhi. With no rainfall reported in the area, residents had no warning as the wall of water surged downstream.

Rajendra Dhungana, the chief customs officer in Rasuwa, told The Kathmandu Post that he initially thought an earthquake had struck. When he ran outside, he saw what he described as "a wall of water, trailing what looked like a plume of smoke, crashing down from upstream." He said the flood rose like a "wave nearly 100 metres high" and swept away the Timure market "within moments".

More than 300 vehicles and trucks waiting at the customs checkpoint were washed away. As the flood surged toward Syaphrubesi and downstream areas, it consumed nearly everything in its path - people, animals, buildings, and public infrastructure.

A statement from Nepal's Prime Minister's Office confirmed that among the missing are 391 foreigners and 44 security personnel.

The scale of those unaccounted for has led officials to warn that this flood may surpass every disaster since the 1993 floods in Sarlahi, Rautahat, and Makawanpur, which killed 1,400 people and have long stood as the country's benchmark disaster.

The destruction of infrastructure has been extensive. According to a preliminary report cited by The Kathmandu Post, the floods have destroyed:

• Nine hydropower projects

• Nine branches of commercial banks

• 19 motorable bridges

• 40 kilometers of highway 

The disaster has exposed critical gaps in Nepal's disaster preparedness. The automatic flood-monitoring stations installed in the upper reaches of the Bhotekoshi River were themselves swept away by the flood before they could transmit any warning, according to Binod Parajuli, a senior divisional hydrologist at the Flood Forecasting Division.

"None of the stations was able to send us an alert," Parajuli told The Kathmandu Post. "We failed in Rasuwa." While warnings sent to Nuwakot and other downstream areas may have saved hundreds of lives, the information arrived too late for communities in Rasuwa.

A technical report from the Flood Forecasting Division revealed that four automated hydrological gauging stations were destroyed by the flood's intensity. The stations at Bhotekoshi and Syaphru Besi in Rasuwa, Betrawati in Nuwakot, and Malekhu in Dhading were all swept away.

A preliminary assessment by the National Disaster Risk Reduction and Management Authority, based on satellite image analysis from Planet Labs, indicated that a "snow-rock landslide" on the Nepal-China border caused a debris-laden flood in the Lhende River. The event originated approximately 20 kilometers northeast of the Rasuwagadhi border crossing.

Anil Pokhrel, former executive chief of the National Disaster Risk Reduction and Management Authority, told The Kathmandu Post that similar problems had occurred in the past when floods originated on the Chinese side, but the issue was not taken seriously enough. "We still don't know how much risk remains," he said. "Unless the Foreign Ministry of Nepal coordinates with the relevant Chinese authorities and creates a system through which early warnings reach our disaster management authority, this problem will continue" .

Following the disaster, Nepal and China held a virtual meeting on Wednesday afternoon, after which China agreed to inform Nepal as soon as water flows begin to rise on its side of the border. However, officials have acknowledged that a 2019 memorandum of understanding on disaster risk reduction between the two countries has yet to translate into an effective, operational mechanism.

Experts are now calling for a permanent, real-time information-sharing and early warning system for transboundary Himalayan hazards. Climate risk reduction expert Ujjwal Upadhyay told reporters that even a one-minute warning could save lives, and two minutes could help people save valuables, while one hour could allow households to move belongings to safer locations.

Survivors have described scenes of unimaginable destruction. Ravindra Nepal, a ward chair in Nuwakot, said the flood wiped out hundreds of houses from Sole to Akkare Bazaar. "I have been stranded at the municipal building since early morning. There is no road or bridge left to get home," he told The Kathmandu Post.

Somlal Dangol, a teacher at Uttargaya Public School, said even a school bus that had gone to pick up students after the flood struck has gone missing. "The destruction is immense. We cannot even begin to comprehend what has happened," he said.

The Nepal Red Cross Society has activated emergency response teams and released emergency stocks including tarpaulins, blankets, rope, first aid kits, and stretchers. The International Federation of Red Cross and Red Crescent Societies has released $1.4 million in emergency funding. India has dispatched 10 tonnes of humanitarian assistance, including temporary shelters, blankets, hygiene kits, solar lamps, and medicines.

The European Union has activated its Copernicus satellite surveillance system to support recovery efforts, while the World Health Organization has dispatched emergency medical supplies.

As search and rescue operations continue, the disaster has underscored the urgent need for cross-border cooperation and robust early warning systems in the face of increasing climate-related hazards in the Himalayan region