Scientists are rushing to understand the exact cause of deadly flash floods that caused a wall of mud and water to form in a Himalayan valley on the China-Nepal border.
What is clear so far is that a large chunk of the glacier collapsed, and 5.2 magnitude The U.S. Geological Survey said the earthquake struck at around 8:37 a.m. local time on Wednesday, causing catastrophic mudslides that spread downstream.
“What we have confirmed is that there was a large ice avalanche, possibly a mixture of ice and rock that separated and then turned into liquid, which then translated into this devastating flood,” said Simon AllenResearcher at the University of Zurich, studying glacial hazards in the Himalayas.
The mountains are shrouded in clouds, meaning the precise chain of events may be better understood once satellites are able to examine it more clearly. The U.S. Geological Survey said it initially reported a magnitude 4.4 earthquake, but subsequent analysis of images and nearby seismic stations confirmed the event was actually a glacier collapse and mudslide.
Analysis so far shows that the glacier front broke off at about 5,200 meters above sea level and began a steep descent to the valley floor, where the ice melted and accumulated sediment. Sugarcaneis a geomorphologist and associate professor at the University of Calgary. “When a lot of rock falls a long way, it generates a lot of heat, which melts a lot of ice, so that could explain some of the water we see in the absolutely horrific video,” he said.
Read more: Millions more at risk of catastrophic flash floods as mountain glaciers melt
Shugar said there is no evidence so far that glacial lake outbursts or earthquakes were the main causes of the event. Shugar is one of dozens of scientists around the world who have been working together over the past 24 hours to determine the cause of the accident.
“Right now we’ve got hydrology data, we’ve got some seismology data, we’ve got some remote sensing data, we’ve got video,” he said. “We have no eyewitness accounts from the valley and no helicopters have flown over the source area.”
Scientist at Nepal Research Institute International Mountain Comprehensive Development Center Working on confirming preliminary assessment Large amounts of ice and rock debris entered the Lundekola River, a tributary of the Botkohi River, triggering a sudden surge of water, sediment and boulders downstream. Last July, the same area was affected by a major flood, according to the center.
“It was like an inland tsunami, traveling nearly 170 kilometers (106 miles)” and affecting a major highway, said Ruth GambleDirector and Lead Author of La Trobe Asia The rivers of Asia’s highlands: from abyssal times to climate crisis. “This is a popular route for international tourists traveling from Kathmandu to Lhasa.”
Researchers have long sounded the alarm about the vulnerability of the so-called Third Pole to warming temperatures and the rising likelihood of disasters.
This highly populated high-altitude region, spread across parts of China, India, Nepal and several other countries on the Tibetan Plateau, is warming. almost double Global average speed. This has led to rapid glacial retreat, with ice in the region shrinking at twice the rate since 2000 compared to previous decades, according to one study. Learning in 2019.
The region’s recorded history isn’t long enough to statistically determine whether ice avalanches like the one Wednesday happened are becoming more frequent, although researchers say that’s the pattern they’re observing.
Glacial lake outburst floods – when water breaks through the ice or rock that holds it in place – are “increasingly common in high mountain regions around the world as our climate changes,” said Adrian McCallumsubject leader in engineering at the University of the Sunshine Coast.
As disaster unfolds in Nepal, many experts in the field is being held An annual summit is held in Chengdu, China, to discuss how to mitigate these risks.
“When you put together all the physical knowledge that glaciers are retreating and permafrost is melting, it certainly makes sense,” said Allen of the University of Zurich. Experts’ conclusion, he said, is that “we are seeing and expecting these events to become more frequent.”
Wednesday’s incident follows a pattern of similar incidents in the Himalayan region in recent years, including landslides that triggered flooding Chamoli, IndiaIn 2021, about 200 people were killed or missing.
“The frequency of cryospheric disasters is now more apparent than ever,” Mohd said. Farooq Azam, senior cryosphere expert at ICIMOD. “The pace is so fast that our continuous efforts cannot cope with such rapid changes.” He said local governments should “take some joint and unified measures to deal with such cross-border dangers.”
Communities have been evacuated ahead of the collapse of other glaciers, including the main one that has buried the Swiss village of Bratten in recent years.
Andrew Gissing, chief executive of the Australian Natural Hazards Research Center, said: “The Himalayan region has historically experienced deadly flash floods. This event appears to have occurred without any warning, leaving people downstream unprepared.” “Early warnings can save lives, and there are global efforts to improve early warning systems.”
Allen said Wednesday’s evacuation could have saved lives had the right equipment and communications been in place.
“This looks like it’s going to be the largest Himalayan disaster we’ve ever seen. So I’m really hoping that this will be a turning point – that there will now be a greater focus, a greater emphasis on reducing risk to these communities,” Allen said.
Photo: Flash floods inundate villages in Nepal and wash away buildings and people; Photo: Prabin Ranabhat/AFP/Getty Images
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