As the death toll from Nepal’s devastating flash floods surged to 270 on Thursday, rescuers launched a desperate race against time to trace hundreds still missing, including 288 Indian nationals.The massive flash flood originating in Tibet swept through central Nepal on Wednesday, devastating several towns and villages, washing away critical bridges and crippling a dozen hydropower projects, as it gushed downstream, affecting multiple districts.According to data released by the National Disaster Risk Reduction and Management Authority (NDRRMA), at least 826 people are missing in the flash floods, of which 590 were tourists.The Ministry of External Affairs said in New Delhi that 288 of the missing people were Indians.A preliminary assessment by Nepalese authorities and a revised analysis by the US Geological Survey point to a glacial collapse or ice-rock avalanche as the trigger for the devastating flash floods.Related news: Nepal mayhem: ISRO’s satellite images show extent of avalanche that caused floodsVillages wiped out in Nepal: Aerial video shows devastating aftermath of floods; expert warns of second floodThe collapse appears to have sent ice, rock and debris into the Lhende river, temporarily blocking its flow before the blockage gave way and unleashed a massive surge downstream into the Bhote Koshi and Trishuli river system.The floods first hit Rasuwa district, near Nepal’s border with Tibet, located around 160 km from capital Kathmandu. A several-feet-high torrent of mud and water eventually gushed downstream, creating havoc in multiple districts.Several videos on social media showed buildings, vehicles, trees, people and animals being swept away.”Thousands of families have lost homes and are missing as of now. We are still trying to ascertain the full extent of the disaster,” Nepal’s Foreign Minister Shisir Khanal said.Nepal Police on Thursday said that the death toll rose to 270, after 93 more bodies were recovered.The bodies recovered so far include 108 in Chitwan, 62 in Nawalparasi East, 27 in Dhading, 20 in Gorkha, 17 in Rasuwa, 15 in Nawalparasi West, 12 in Nuwakot, and nine in Tanahun, according to Nepal Police spokesperson Abi Narayan Kafle.According to officials, 44 Nepali Army personnel, 28 Nepal Police personnel and 13 Armed Police Force personnel are among those whose whereabouts remain unknown. Similarly, around 160 people working at different hydropower and customs offices have been missing.The Nepal Tourism Board said 590 tourists — 476 foreigners and 114 Nepalis — have been reported out of contact. The foreign tourists were from more than 30 countries, including the US, Canada, South Africa, the UK, Italy and South Korea.Most of the Indian tourists, meanwhile, were en route to Kailash Mansarovar in Tibet and Gosainkunda in Nepal’s Bagmati Province, officials said.Search and rescue operations are continuing in the flood-affected areas, with security personnel and local authorities scouring the riverbanks and downstream areas for those missing.Officials rescued 27 foreign tourists stranded in Rasuwa on Thursday. They include 11 Indian nationals, four South Koreans, two Italians and two US citizens. The nationalities of the other eight are yet to be confirmed by the Nepal Tourism Board. They were airlifted to Kathmandu in the afternoon with the help of Nepal Army.The floods have damaged 35 motorable bridges, 45 suspension bridges, and 40 km of black-topped road, mainly in central Nepal.Efforts are under way to reopen the Galchhiâ-Baireni road in Dhading, which was blocked following the flash floods in Rasuwa. This road is crucial because it connects Kathmandu to the rest of Nepal, serving as a major staging and transit zone for heavy and light traffic during regional blockades and disaster management operations.Armed Police Force personnel and local residents have been deployed to clear the road. Security personnel and locals are working to remove the debris and resume traffic along the route.Nepal Prime Minister Balendra Shah on Thursday visited Bidur Municipality of Nuwakot district for the inspection of the flash flood-affected areas.A preliminary assessment on Thursday suggested that the flash flood was caused by an ice avalanche upstream blocking a river on the Nepal-Tibet border, disaster management authorities were quoted as saying by My Republica news website.The assessment suggests that the flood in the Trishuli river was caused by an ice avalanche upstream blocking the Lendhe river.The NDRRMA said that a debris-laden flood occurred in the Lendhe river following an ice-rock landslide at the border, about 20 kilometres northeast of Rasuwagadhi.