NEW DELHI — The disaster came with no warning. Mist filled the air, and the earth started shaking. Pushkar Singh ran for his life.
“The river was flooding with massive boulders. The trees were falling,” said 37-year-old Singh. “It was terrifying.”
Singh is a resident of Pang village in the mountainous state of Uttarakhand, home to more than 10 million people in northern India where a deadly cascade of rock, debris and icy water earlier this month wreaked havoc, sweeping away bridges and a power plant. Officials recovered the bodies of 58 people, and nearly 150 others remain missing, as rescue operations continue into the second week.
Experts around the globe are studying satellite imagery to understand what caused the avalanche. But the massive flooding illustrates the risks of development in an area vulnerable to the accelerated effects of climate change: The Himalayan range, the Hindu Kush, the Tibetan Plateau and their peaks are known as the “Third Pole” because they contain the largest repository of glacial ice in the world outside the Arctic and Antarctica.
All that ice is susceptible to the warming temperatures in the region, which have outpaced the rate of global average warming in recent decades. The melting ice and expanding glacial lakes heighten the risk of landslides and floods. Environmentalists say the construction of dams and power projects and road-building development works have put millions of people in a precarious position.
Experts say the massive flooding was caused by the collapse of both a section of rock and a “hanging glacier” — a huge chunk of ice — along a steep slope. The mass plummeted into the valley at a high speed, colliding at the base with glacial sediment. The resulting slush crashed downstream into the Rishiganga River.
“The water came down like a tsunami,” said Kalachand Sain, the director of Wadia Institute of Himalayan Geology, whose team conducted a field study last week.
International researchers have largely ruled out the most obvious climate-related threat: a glacial lake outburst flood, a known hazard in this region that happens when retreating glaciers leave unstable lakes behind them at high altitudes. The changing climate is making these floods worse.
“I can say pretty conclusively, no glacial lake outburst flood occurred,” said Dan Shugar, an expert on glacial hazards at the University of Calgary.
Shugar estimates that 25 million cubic meters of rock and ice mass fell. Upon impact, he said, the ice could have been crushed and melted by the huge heat generated by the fall, leading to the formation of a large amount of water and debris that cascaded downhill, crashing against multiple dams and creating a giant surge.
Were rising temperatures the spark? Possibly, but scientists can’t say for sure yet. Both ice and permafrost hold together rock in high mountain areas, meaning that thawing can destabilize mountain walls, but no one is certain that’s what occurred here. Landslides and avalanches sometimes happen on their own.
“We can never know whether this piece of particular rock would have fallen with or without climate change,” said Mylène Jacquemart, a scientist at the University of Colorado at Boulder who studies the role of climate change in hazardous mountain conditions. “Quite likely that it would have. It’s really steep. Rocks fall, they do all the time. But the overall signature that we’re seeing when we look at all of the events globally, yeah, this seems to be more and more of a problem.”
The melting of the glaciers in the Himalayas in particular is dramatic and accelerating, recent research has found, with the pace of change much faster in the 21st century than the 20th.
“This area is in the tight grip of climate change,” said Joerg Schaefer, a glaciologist at the Lamont-Doherty Earth Observatory at Columbia University, who has documented widespread losses of glacial ice across the region over the past four decades. “This is one of the areas where climate change will be most directly hazardous, and on the shortest time scales.”
In the part of the Indian Himalayas where the disaster occurred — the Nanda Devi Biosphere Reserve — glacial retreat is well documented. A study published last year looked at the area’s major glaciers and found that they had lost approximately 10% of their area since 1980, equivalent to 10 square miles of ice-covered slopes. The prominent Uttari Nanda Devi Glacier, for instance, is retreating at 72 feet per year.
The pace of warming in the Nanda Devi region appears possibly even a bit above average, with one long-standing temperature station about 80 miles from the disaster showing approximately 1.4 to 1.6 degrees Celsius (2.5 to 2.9 degrees Fahrenheit) of warming since the late 19th and early 20th century.
The latest disaster is “proof that the climate crisis can no longer be ignored,” said Abinash Mohanty, a researcher at the Delhi-based Council on Energy, Environment and Water. In a recent report, he found that the frequency and intensity of extreme flooding and landslides in Uttarakhand had increased fourfold in the past five decades.
Experts have long warned about the role of infrastructure projects in exacerbating the impact of disasters like these.
Ravi Chopra, who heads the People’s Science Institute in Dehradun, the largest city in the state, said he views the disaster as “two events.” The falling of the rock and ice mass is a natural event, he said, but as it rolled down the river, it encountered barriers like bridges and dams. The floods picked up more debris and moved with greater speed after smashing into these barriers, which he called a “man-made disaster.”
In 2013, Uttarakhand was the site of one of the worst natural disasters in the country after massive floods and landslides triggered by heavy rains killed thousands of people. In its aftermath, Chopra led a committee, following a Supreme Court order, that recommended no dams be built in “para-glacial zones” — areas where glaciers have retreated and left behind massive amounts of debris.
The two hydropower projects damaged in the latest flood are in these para-glacial zones, he said. The committee’s recommendations were challenged by developers in court. The case is ongoing.
A day after the disaster, Trivendra Singh Rawat, the chief minister of Uttarakhand, urged people not to use the tragedy to “build an anti development narrative.”
For Singh, the local resident who witnessed the disaster unfold, the past weeks have brought forth long-held fears.
“We were always scared that something would happen because of the constant blasts” from the construction, he said. Local protests did not stop the power projects.
“We are scared of a repeat of flash floods, but what can we do?” he said. “We cannot leave our village.”
Mooney reported from Washington. The Washington Post’s Taniya Dutta in New Delhi contributed to this report.