Jiwan Jyoti, a 50-year-old Lexington resident, has been unaccounted for since a glacial collapse triggered catastrophic flooding near the Nepal-China border on Wednesday, Aug. 26.

Jyoti had traveled to Nepal on a birthday pilgrimage through the Himalayas and was preparing to cross into Tibet that morning when she called her family at home, her daughter Hunar Rai told NBC Boston. About 30 minutes later, an avalanche and subsequent flooding and mudslides devastated the border town of Rasuwagadhi. Satellite images showed a checkpoint and bridge wiped out, with cars, trees and people swept away.

"She'd been thinking of doing this for a while, and I guess she gifted it to herself," Rai told NBC Boston.

Rai said her mother was traveling with a group of about 40 people, most of them foreigners, including several Americans. Many of the missing were on a pilgrimage to Mount Kailash in Tibet, a sacred site for Hindus, Buddhists and others, Newsweek reported.

Nepal authorities published a preliminary list of those "out of contact" after the disaster. Jyoti's name appears on it. The list does not confirm whether those named are injured, stranded or unable to communicate.

Manmeet Singh Meet, a close friend of Jyoti who told Newsweek he has known her for more than 15 years, said he is helping support the family. He described the wait as heartbreaking.

The expedition company Himalayan Glacier said on social media that communication from the disaster zone has been extremely difficult and that it was working to relay information from the ground.

The U.S. Geological Survey determined the seismic event was a magnitude 5.2 glacial collapse, not an earthquake, that sent debris flowing downstream. Climate researchers at the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD) said the Lhende Khola river system has now flooded twice in 14 months, CBS News reported.

The ICIMOD said an ice rock avalanche from a glacier on the Nepal side blocked the river and released a sudden surge downstream.

As of Saturday, Aug. 29, the death toll stood at 669 in Nepal and seven in China's Tibet, with nearly 3,000 people still missing, according to a USA Today report. About 500 of the missing are foreign nationals. The Red Cross estimated nearly 93,000 people were affected.

The U.S. State Department said it was aware of about 90 Americans impacted by the floods. The State Department said three Americans had been rescued as of Friday, Aug. 28, and that it was not aware of any American deaths, according to CBS News. Officials said they were providing monetary assistance and communicating with the Rai family as efforts to locate Jyoti continued.

Rescue crews paused operations Friday after a lake that formed during the initial flooding began to overflow. Work resumed after water levels dropped, but poor weather continued to ground helicopters on Saturday.

The Nepal Tourism Board said 187 people had been rescued as of Saturday, including three Americans. Search and rescue operations remain active across the region.