The confirmed death toll is rising closer to 400 people after devastating flash floods that hit the Nepal-Tibet border early Wednesday, sweeping away roads, bridges and entire villages, with more than 1,000 still missing.

The U.S. State Department said about 90 Americans are among the people unaccounted for. The State Department said, as of Thursday morning, was not aware of any confirmed deaths of U.S. citizens.

The U.S. Geological Survey says a glacial collapse triggered the floods, after initially reporting the event as a 4.4 magnitude earthquake.

Chinese surveillance footage from the Tibetan side of the border shows a huge wall of mud and debris crashing over buildings and engulfing roads as people desperately try to flee the torrent.

Residents have described their terror as great waves of water barreled down valleys, burying people and homes under the mud. Santa Tamang, a 25-year-old university student who lives in one river valley, spoke to NPR by phone.

Tamang said her family was able to rush to higher ground, carrying her elderly grandmother with them, but their home was washed away. “Everything is gone. My childhood, my family, my community,” Tamang said.

Nepal is a popular tourist destination, and many of those missing are foreign nationals — more than 600, according to the figures from the Nepal Tourism Board, although figures varied. In addition to the Americans, Nepal said people from India, the United Kingdom, Australia and Canada were among the missing.

A resident walks along a street covered in mud following flash floods and a landslide disaster in Devighat, in Nepal’s Nuwakot district, on Wednesday. A massive flood and landslide disaster wiped out entire settlements.

Prakash Mathema/AFP via Getty Images

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Prakash Mathema/AFP via Getty Images

India’s Foreign Ministry counted 290 Indians who were “not contactable” as of 8 p.m. local time.

Chinese officials said 558 people were missing on the Tibet side of the border, including 260 foreign nationals.

Many of the missing are Hindu pilgrims, who were journeying to Kailash Mansarovar, a high-altitude site in Tibet revered by Hindus and Buddhists.

Rescue efforts, still in their first stages, have been hampered by the fact that the floodwaters have washed away entire roads. Riaz Lodhi, country director for the World Food Programme in Nepal, said rescue workers are trying to dig people out of the mud and that the Nepalese government is deploying helicopters to help.