When Gyanendra Kachhapati arrived two years ago to check out a mountain trout fishing center he owned near the Tibetan border, he noticed that the Melamchi River was flooding, despite clear skies.
He quickly sent his son home on a motorcycle to warn his wife and others living downriver. They survived the fast-growing deluge, but Kachhapati was not so lucky.
“I came home to save my mother on my father’s direction, because our house was on the bank of the Melamchi River,” recalled his 29-year-old son Upendra Kachhapati.
But when father and son spoke on the cell phone, Gyanendra “got carried away while talking,” said his son – one of five people killed near the riverside center that day.
All told, the flooding, caused by a collapse of a glacial lake near the Tibetan border, killed 24 people and damaged about $905 million in infrastructure, including 570 homes, according to Nepal’s National Disaster Risk Reduction and Management Authority.
As climate change warms the planet, makes rainfall more extreme and accelerates the melting of glaciers, Himalayan countries such as Nepal face increasing risks of flooding, often caused by glacial lake eruptions.
Larger amounts of meltwater from the glaciers gradually build up in mountain lakes, putting increasing pressure on the earth and rocks and holding them in place. They can suddenly collapse, causing massive downstream flooding.
While some surveillance equipment and early warning systems are in place to alert downstream communities, a lack of cross-border information sharing between Himalayan countries — including China, India and Nepal — is hampering conservation efforts, analysts warn.
“There are many dangerous glacial lakes in Tibet. If they burst, it will directly affect Nepal and the damage will be far greater than the Melamchi disaster,” warned Narendra Khanal, a former chief of geography at Tribhuvan University in Nepal.
Northern Nepal borders China for nearly 1,400 km, and the country’s main rivers – the Koshi, Gandaki and Karnali – flow in from Tibet.
Maps published by the intergovernmental International Center for Integrated Mountain Development (ICIMOD) and the United Nations Development Program (UNDP) show 3,624 glacial lakes along the three river basins in 2020, of which 2,070 are in Nepal, 1,509 in China, and 45 in India.
Of those, 47 are considered to be at particular risk of explosion, 25 of which are in Tibet, the agencies said.
But little real-time information is being shared across international borders about the state of the lakes, even as they grow in size, because formal data-sharing mechanisms are largely not yet in place, analysts said.
That raises fears in downstream communities, which are themselves growing in size, that deadly flooding could happen without any warning.
“We don’t take catastrophic glacial lake eruptions seriously,” said Deepak KC, a climate change expert at UNDP in Kathmandu.
The collapse of a one-hectare glacial lake in Tibet in 2016 caused $200 million in damage along Nepal’s Bhote Koshi River system, he said, wiping out 125 homes and a hydroelectric power station, though there were no fatalities.
But “other lakes are 200 times bigger than that one and could explode any minute. What will our situation be if that happens?” he asked.
Call to share data
As the danger from glacial lakes in the Himalayas grows, researchers and officials have sought more formal sharing of lake data and early warnings between Nepal, China and India, they said.
Kamal Ram Joshi, director general of Nepal’s Department of Hydrology and Meteorology, said his agency had requested real-time data on the status of glacial lakes on shared river systems from China and India, but had not received a positive response so far.
“We are in a difficult position due to the lack of data on the glacial lakes,” he said, noting that the agency had not looked for historical data, but only for real-time measurements.
“We always poll China and India to provide real-time data in various forums, such as the World Meteorology Forum,” he said.
Rishi Ram Sharma, a former director of the hydrology and meteorology department until 2019, said the agency had already addressed requests to China during his tenure.
One challenge appears to be the political sensitivity of data from Tibet, researchers said.
China has provided some assistance by e-mailing the chief of Nepal’s Dolakha District in June 2021 about a blockade of China’s Tamakoshi River due to large-scale landslides, said Ranjan Kumar Dahal, an associate professor of geography at the Tribhuvan University.
That warning, passed on to downstream communities, saved lives, he said.
Khanal, from Tribhuvan University, said Nepal should work harder to try and secure a regular flow of such needed information.
“Chinese scientists have told us that the government of Nepal should take initiatives. I think the government of Nepal is not taking it seriously either,” he said.
Money may be part of the problem, with supplier countries sometimes requiring payment for data, Khanal said.
Residents along transboundary rivers say better data sharing can’t come too soon.
Nima Gyalzen Sherpa, chairman of the rural municipality of Helambu, which has asked the government of Nepal to push for more international information sharing, said warnings even half an hour before a flood could significantly limit losses.
“We could inform the residents of the banks of the Melamchi River. Then at least one human life is safe,” he said.
Upendra Kachhapati, the son of the man killed in the fishing center during the Melamchi flood, said residents are in the dark for now.
“What time a flood will come from the Himalayan region, we cannot predict,” he said. What is happening in the high Himalayas? We need information.”