A tour operator in Kathmandu has told of his desperate search for dozens of trekkers and staff members – including his own brother – who remain missing three days after devastating floods struck at the border between Nepal and the Chinese region of Tibet.Gopal Thapa, managing director of Leaf Holidays, Treks and Expeditions, said 55 people travelling with his company are still missing – 46 clients and nine of the company's workforce. Among them is his 34-year-old brother, who was guiding the group and is a father of two.“I spoke to my brother at around 8.30 Nepal time [on Wednesday, August 26],” Mr Thapa told The National. “After that there is no connection.”The group included pilgrims from several countries, including Malaysia, Singapore, Ukraine, Italy, the US and Britain, as well as Nepalese staff. Mr Thapa said they were going through immigration procedures near the Nepal-China border and preparing to continue towards Mount Kailash when the disaster occurred.He learnt of the floods about 15 minutes later and immediately tried to reach the area by helicopter. “I tried to find them. I couldn't find them,” he said. He has since been working with police, the army, local authorities and families, but said there had been no news of any of the 55 people.Nepal Police said in its latest update on Friday afternoon that 547 people are confirmed to have been killed in the disaster so far, with a further 1,473 injured. More than 4,000 police personnel are responding.Gopal Thapa, managing director of Leaf Holidays, Treks and Expeditions. Shazia Ahmed / The NationalShow caption: Gopal Thapa, managing director of Leaf Holidays, Treks and E…'They are my family'When The National met Mr Thapa in Kathmandu, he opened photographs of the missing group on his computer and pointed out members of his staff and pilgrims one by one. For him, the loss is deeply personal.“Nine staff are my family,” he said. “They are my staff, they are my family. The people who are coming for the pilgrimage, they are also all my family. We are praying. We are looking for them.”Hundreds still missingMany people killed or missing following the catastrophic flash floods and mudslides were pilgrims headed to Kailash Mansarovar, a high-altitude site in Tibet revered by Hindus and Buddhists, among others.Nepalese authorities have said more than 650 foreigners are still unaccounted for following the flash floods, which were triggered by a high-altitude glacier collapse along the Nepal-Tibet border.The National spoke to several tour companies that had groups travelling through the Rasuwagadhi border region when the floods struck. They described losing contact with entire groups within minutes and spending the days since contacting authorities, embassies and families in an effort to establish whether anyone survived.Govind Sharma, managing partner at Kathmandu Holiday Tours and Travels. Shazia Ahmed / The NationalShow caption: Govind Sharma, managing partner at Kathmandu Holiday Tours a…Govind Sharma, managing partner at Kathmandu Holiday Tours and Travels, told The National that 17 people linked to his company, including three members of staff, remain missing. Their last contact with the group was at about 7am or 8am on Wednesday near the immigration area, he said.“All the 17 passengers we have, including our three staff, they all are missing,” he said. “We are still searching for them.” Mr Sharma said his company was keeping in contact with families while working with the government, army and rescue teams.Mr Sharma lived in Dubai for 21 years and expressed gratitude for the UAE's assistance to Nepal following the disaster. “In this situation, the UAE government has supported Nepal. For that, all of Nepal is grateful.”The National spoke to another Kathmandu tour operator, The Trekkers' Society associated with the Isha Foundation in India, which said 77 foreign pilgrims and 12 Nepalese staff connected to its group remain missing. The pilgrims had completed their Mount Kailash journey and were returning from Tibet to Nepal on Wednesday.The company said its last contact came at about 8am, when it was told the group had reached immigration. The floods are believed to have struck the area shortly afterwards. “Our best guess is they were at the immigration centre itself,” a company representative told The National.The company said it had submitted the names of the missing to government authorities and was seeking any information about their whereabouts. “We are doing our best to get even a little information about them,” the representative said.At Alpine Treks, staff said 16 foreign nationals linked to the company, including 12 British and four South African travellers, were caught up in the disaster. The search has been made more difficult by widespread damage to roads, bridges, electricity supplies and telecoms infrastructure.Across Kathmandu, the offices that would normally be organising pilgrimages and trekking expeditions have instead become points of contact for families, embassies and authorities searching for the missing.Play00:40Nepal army rescues hundreds from hydropower tunnelCritical aid driveBishal Kumar Bhandari, chairman of the Nepal Red Cross Society, said communities in Rasuwa and Nuwakot had been cut off after bridges were swept away and electricity and telecoms infrastructure was damaged.The Red Cross has directly assisted more than 2,000 people and is providing food, drinking water, temporary shelter, hygiene supplies, ambulances and other assistance. But Mr Bhandari said the disaster had left scars extending far beyond the physical destruction. “People are psychologically blocked,” he said. “In the flood, they not only lost their house, they lost their emotion,” he told The National.He recalled meeting a woman in her seventies who had lost so much that she asked him: “Why didn't this flood take me away?”“I was very quiet, I did not have any answer to give her,” he said.