A sudden flash flood swept through Nepal's Rasuwa district near the Tibet border on Wednesday, August 26, killing at least 22 people and leaving hundreds of others out of contact, according to the latest reports from Nepal. The flooding damaged settlements, roads, bridges and hydropower infrastructure along the Bhotekoshi River.
The exact cause of the flood has not been officially confirmed.
A preliminary assessment by Rijan Bhakta Kayastha, a professor at Kathmandu University and climate researcher, suggests that an ice avalanche may have blocked the Lhende River, causing water to build up before a sudden surge downstream. Kayastha said the assessment was based on preliminary findings and discussions with scientists in Nepal and China.
A magnitude 4.4 earthquake was also recorded in Tibetan territory shortly before the flooding. However, available information does not establish that the earthquake caused the avalanche or the subsequent flood.
What caused the Nepal floods?
The initial assessment points to a possible blockage of the Lhende River by an ice avalanche.
Kayastha said an ice avalanche appears to have fallen into and blocked the river, allowing water to accumulate before the blockage gave way and released water downstream into the Bhotekoshi River.
Shanti Mahat, spokesperson for Nepal's National Disaster Risk Reduction and Management Authority, said the agency had received preliminary information that an ice avalanche had blocked a river.
However, Mahat said the agency had not yet received official confirmation of the information. The information had been shared by the International Centre for Integrated Mountain Development, which had received it from sources in China.
Nepal's Department of Hydrology and Meteorology is also investigating whether a glacial lake outburst may have contributed to the flooding.
Did an earthquake trigger the flood?
A magnitude 4.4 earthquake was recorded in Tibetan territory at 8:37 am, according to the US Geological Survey. It was located around 47 kilometres north of Gosainkunda.
Kayastha said the earthquake occurred on the Tibetan side around the same time as the suspected ice avalanche.
The timing has led to the earthquake being examined as a possible factor, but there is currently no confirmed evidence establishing that it triggered the avalanche or the flood.
The flood reached the Bhotekoshi River at around 9 am local time, coming from the Tibet side, according to officials cited by AFP. It affected Rasuwa and Dhading districts near the Tibet border as well as Nuwakot district, southwest of Kathmandu.
Was heavy rainfall responsible?
The Department of Hydrology and Meteorology said there had been no heavy rainfall in the Rasuwa area on Tuesday or Wednesday.
The department also said significant rainfall was not expected in the area on Wednesday, with rain-bearing clouds expected to develop from Thursday.
Kayastha said the sudden nature of the flooding was consistent with a rapid release of water from an upstream blockage rather than a conventional rainfall-driven flood.
Which parts of Nepal were affected?
Rasuwa district was among the worst-affected areas, particularly communities around the Nepal-China border.
The flood also affected parts of Nuwakot and Dhading as water moved downstream through the Bhotekoshi and Trishuli river systems.
The flooding damaged roads, bridges, settlements and hydropower infrastructure.
The Bhotekoshi River also carries an important route towards the Rasuwagadhi border crossing with China, which was affected by the flooding.
How many people have died?
As of the latest update published by The Kathmandu Post at 5:50 pm on August 26, 22 people had been confirmed dead following the flash flood.
The death toll may change as search-and-rescue operations continue and authorities assess the affected areas.
How many people are missing?
Hundreds of people remain out of contact.
According to the latest information from the Nepal Tourism Board cited by The Kathmandu Post, 384 people were reported out of contact, including 291 foreign nationals and 93 Nepali nationals.
The figure is based on preliminary information and does not mean that every person on the list is confirmed to have been swept away or injured.
Authorities and tourism agencies are continuing to verify the whereabouts and safety of those who have not yet been contacted.
Are Indian nationals among those missing?
Yes. The supplied report says 105 Indian nationals and 37 NRIs were among the foreign nationals reported missing after the flooding. The figures were based on preliminary agency-wise records received by the Nepal Tourism Board from travel and tourism companies.
The figures remain subject to verification.
Many of those out of contact were travelling towards Tibet for the Kailash Mansarovar Yatra.
What happened to the Kailash Mansarovar pilgrims?
A total of 384 travellers, including 291 foreign nationals and 93 Nepali nationals, were scheduled to cross the border on Wednesday, according to the information cited in the supplied report.
The report said contact had not been established with most of the travellers.
Among the foreign nationals reported out of contact were 105 Indian nationals and 37 NRIs. The Nepal Tourism Board said these figures were based on preliminary records received from travel and tourism companies.
Being listed as missing or out of contact does not by itself confirm that a person has died or been injured.
What damage has been reported?
The flooding damaged settlements and critical infrastructure across the affected districts.
Roads and bridges were washed away, while hydropower facilities were also affected.
The disruption has made access to some areas more difficult and has complicated search-and-rescue operations.
The latest Kathmandu Post report said communications problems and poor weather were also hampering rescue efforts.
What are authorities doing?
Nepal's security forces have been involved in search-and-rescue operations across the affected areas.
The Nepal Police, Armed Police Force and Nepali Army have been deployed to assist with rescue and relief operations.
Authorities have also been working to establish contact with people who remain unaccounted for.
The Indian Embassy in Nepal has issued emergency numbers for Indian nationals affected by the floods:
+977 985 131 6807
+977 970 910 7500
The numbers can also be contacted through WhatsApp, according to the supplied report.
What is still unclear about the Nepal floods?
The precise trigger for the flash flood has not yet been established.
Rijan Bhakta Kayastha's preliminary assessment suggests that an ice avalanche may have blocked the Lhende River. The National Disaster Risk Reduction and Management Authority has received similar preliminary information, but its spokesperson said official confirmation had not yet been received.
The Department of Hydrology and Meteorology is also investigating whether a glacial lake outburst occurred.
A magnitude 4.4 earthquake was recorded in Tibetan territory around the same time, but a direct link between the earthquake and the flood has not been confirmed.
Further assessment, including examination of the upstream area, is expected to provide more information about what caused the sudden release of water.
TL;DR | News At A Glance
A flash flood swept through Nepal's Rasuwa district near the Tibet border on August 26.
At least 22 people have been confirmed dead, according to the latest update from The Kathmandu Post.
384 people were reported out of contact, according to preliminary figures cited from the Nepal Tourism Board.
The preliminary list includes 105 Indian nationals and 37 NRIs.
Rijan Bhakta Kayastha, a professor at Kathmandu University and climate researcher, said a preliminary assessment suggested that an ice avalanche may have blocked the Lhende River.
Nepal's disaster management authorities have also received preliminary information about a possible ice-avalanche blockage, but said it had not been officially confirmed.
A magnitude 4.4 earthquake was recorded in Tibetan territory at 8:37 am, according to the US Geological Survey.
Authorities are also investigating whether a glacial lake outburst may have contributed to the flooding.
Rescue teams continue to search for people who remain out of contact.
