Emergency workers on Thursday were searching for more than 1,000 missing people after a massive flash flood poured into the Trishuli River valley along the border of Tibet and Nepal's Rasuwa district, crashing through villages where thousands of people live and sweeping away bridges, homes, and miles of roads.
The disaster stunned officials in the area, where there had been no rainfall before the floodwaters and mudslide overtook the region, killing at least 332 people, according to numbers confirmed so far by authorities in Nepal.
Intense videos circulating on social media Wednesday showed people attempting to run away as water and mud crashed into villages in the region.
Tom Fletcher, the United Nations humanitarian chief, said he had mobilized $2 million from the UN Global Emergency Fund "to save lives with emergency medical care, shelter, water."
The secretary-general of the Nepal Red Cross told CNN that about 20,000 houses have been "swept away" in the region.
"These people do not have anything," said Rishi Khanal. "To feed them for some time, some days is a very serious thing to us... The shelter problem is there. The drinking water problem is there."
A police officer in the village of Syabrubesi told the Times that waves of water crashed into his police station Wednesday morning, right after he got off the phone with a friend who had warned him a flood was headed toward the town.
“One of my senior officers and I were together when the wave struck. I was thrown out, but he was unlucky and was buried or swept away,” he told the newspaper. “I cannot explain how big the waves were. They engulfed several-meters-high buildings in a fraction of seconds... It wasn’t just water. It was a combination of boulders, sand, and thick sludge.”
Seven people were working at the station when the flood hit, and the officer is one of three who have been found alive. He said he was concerned that the other four are among the missing.
Homes, schools, government buildings, and the office of a hydropower project are among the infrastructure destroyed in Syabrubesi.
A group of geologists and glaciologists made an initial assessment finding that an "ice avalanche"—a massive chunk of ice that fell off a glacier in the mountainous region and into the valley below, was likely at least partially to blame for the flash flooding, but noted that it was too early to rule out other or additional causes.
Satellite imagery appeared to show that "a glacier in the area basically snapped off in a clean break, allowing it to fall just over a vertical kilometer to the valley bottom,” Daniel Shugar, a geologist at the University of Calgary in Canada, told The New York Times. "The bottom looks like a bomb exploded—it’s just deposits from the broken-up glacier."
The chunk of ice was likely about 2,000 feet wide, Shugar told the Times, and fell nearly 4,000 feet—a fall that "pulverized" the ice into water.
Shugar noted that satellite images from the day before the flooding showed that snow had vanished from the tops of nearby mountains, suggesting that warm temperatures may have melted the ice.
More than 160 glaciers in Nepal have entirely melted in recent decades, as scientists have warned that continued fossil fuel extraction is heating the planet and causing dangerous extreme weather. The area of the country's glaciers also shrunk by about one-quarter between 1970-2010.
At The Conversation, Levan Tielidze, a research fellow in glacial geomorphology at Monash University, wrote that "it’s too early to say this was the exact cause. But we know that the great ice stores of the Himalayas—known as the world’s 'third pole' because it contains the largest amount of snow and ice after the Arctic and Antarctic—are no longer safe."
Tielidze continued:
What happened in Nepal is likely due to an enormous ice-and-rock landslide sweeping down a mountain pass and gathering up ice, water, rock, trees and dirt.
The landslide was so large it was originally thought to be an earthquake, as the seismic energy registered as a 4.4 magnitude quake on seismographs.
By the time it reached Gyirong Port—a China-Nepal border crossing—the wall of debris resembled a tsunami of dirt. Early estimates suggest the wave may have been 30 metres high.
Rising global temperatures have been linked to previous collapses of glaciers, including in Switzerland last year when the Birch Glacier wiped out nearly an entire town of 300 residents, who had evacuated before the disaster. Eleven mountain climbers were also killed by a glacier collapse in Italy in 2022.
