Flash flood in Nepal and Tibet kills hundreds, leaves thousands missing as glacier instability worsens

More than a thousand people are missing and at least 400 people are dead after flash flooding tore through Nepal and Tibet early Wednesday. According to initial assessments, a massive chunk of ice snapped off a glacier and tumbled thousands of feet into the valley below. Rock, ice and mud plunged down for miles, washing away communities along the river.

Scientists say glaciers in this region, and around the world, are increasingly unstable because of human-caused global warming. Across the mountains of Nepal and Tibet, climate change is causing glaciers to melt at an alarming rate.

Planet-heating emissions from burning fossil fuels such as oil, gas and coal are the primary driver of climate change. Scientists say that in addition to reducing climate pollution, renewable energy and battery technologies are increasingly price competitive with traditional energy sources.

"There's no question that this event was made more likely because of climate change and that we're seeing more likely other similar glacier hazards occurring," says Twila Moon, deputy lead scientist at the National Snow and Ice Data Center at the University of Colorado Boulder.

Footage from the Chinese-administered Tibet side of the border with Nepal shared on local media showed a massive gush of water sweeping over a port building as people fled.

As the water barrelled down, residents filmed it sweeping away a bridge and washing away riverside settlements.

The flooding was made more severe because it happened during the heavy rains of the monsoon season, says Mohammad Farooq Azam, an expert at ICIMOD, an environmental advocacy group that focuses on Asia's high mountains. "Everything is fully saturated already," Azam said. "The rivers are swollen."

This flood is part of a trend, said Arun Bhakta Shrestha, an expert on climate change and the Himalayan glaciers.

"If you look at the whole Hindu Kush Himalayan region," he said, "it seems like the frequency, the types of those hazards are increasing." Shrestha said everything points to climate change as the reason.

The world will see "more and more events like this," says Alton Byers, a faculty research scientist at the Institute of Arctic and Alpine Research at the University of Colorado Boulder. "Things are getting warmer," he says.

Permafrost on the mountains, the continuously frozen soil and sediment, is now changing, said Byers. He uses the analogy of a stick of butter left out of the refrigerator. "It's going to get softer," he says. "And it's going to lose its structural integrity."

Preliminary reports indicate that Nepal's flood warning system wasn't equipped to handle these floods. That's despite significant government investment in flood warning systems over the last decade in Nepal. Many flood-prone valleys in the country have warning alarms, but as NPR has reported, the government has struggled to keep up with the cost of maintaining the systems.

NPR's Rebecca Hersher contributed to this reporting.