Nepali labourer Bibek Kumal was ‌digging a toilet pit outside a newly built house on Wednesday when a wall of water, mud and rock came roaring down, sweeping him and everything near him away.Kumal (24), ​was working in Bidur, downstream from the worst-hit Rasuwa district, near Nepal’s Himalayan border with China’s Tibet, when he heard a hissing sound. His four co-workers, standing above the 1.5 metre-deep pit, shouted at him to get out and run.By the time he scrambled out of the pit, his co-workers had already fled.“I started running. Then a wall ​of water came thundering down as if it was an earthquake,” Kumal said from his bed at Kathmandu’s National Trauma Centre, his brother Dinesh sitting beside him.The torrent swept him downstream ⁠amid mud and debris, but “luckily I was stuck up in a mango tree”, he said. “Had there been no mango tree, I ‌would ‌have ​been washed away to death.”How deadly flash floods hit Nepal-Tibet border Video: Reuters About 1,500 people are missing across Nepal and China’s Tibet, authorities said on Thursday, after a wall of mud and rock collapsed into a ​Himalayan river, causing the catastrophic flash floods.Three others also injured in the flood were being treated alongside Kumal, ⁠as more people were transported to the capital Kathmandu. Outside the hospital, well-wishers, friends and onlookers crowded the small compound of the trauma centre.The ‌flood devastated settlements and infrastructure downstream.Security footage captured ⁠on the Chinese side of the border showed many people ⁠fleeing before a wall of ​rock, mud and water destroyed buildings and vehicles and took many lives. Kumal said as he clung to the mango tree, he watched the house where he had been working disappear.Police later reached him and pulled him to safety. He suffered injuries to his right leg after being struck first by the water and then by a large stone. His own home, located elsewhere, escaped damage, he said.Mostly mountainous Nepal experiences ‌deadly floods and landslides every monsoon season, ⁠and is prone to other natural disasters. As a teenager, Kumal lived through the devastating 2015 earthquake that killed nearly 9,000 people.In the hospital bed opposite him, 11-year-old Rihana Lamichhane narrowly escaped.“I was at school. They closed the school because ‌of this and asked us to go home,” she said. “As I was crossing the river, suddenly flood water came gushing down.”She suffered injuries to her chest and leg but ​said: “I am happy to be safe. I have no idea what happened to my friends.”Her mother, ​Rita, said she rushed to find her daughter after receiving a call from a friend.“I am happy nothing serious happened to my daughter,” she said. “I am relieved to find her safe.”- Reuters[ About 1,500 missing as rescuers struggle to reach survivorsOpens in new window ]