Hundreds feared dead as new flood threat stalls rescue efforts in Nepal, Tibet

This morning, a new flood threat is endangering the search and rescue efforts along the Nepal-China border

A lake, formed by Wednesday's massive glacial collapse, is starting to overflow

The death toll from that devastating flood, meanwhile, continues to go up, with hundreds still missing on both sides of the Himalayan border

Reporting from the remote disaster zone is inconsistent, but authorities now say more than 450 people are dead

and more than 1,400 are unaccounted for. The State Department says about 90 Americans may

have been affected in Nepal and China. Three have been rescued, and so far there are no known

American deaths. President Trump called the disaster a terrible thing Thursday. He says the U.S. has offered to provide whatever help is needed

We are sending aid, and we've spoken to the leadership, and we let them know anything they

want will have. And there were 50, maybe 60 Americans over there. We haven't gotten the

full list yet, but hopefully they're okay. But that looked pretty, that looked like something

that people will not be, somebody will be lost, unfortunately. And we're now getting a clearer

picture of what triggered the disaster. Scientists studying satellite images say bedrock beneath a

glacier on Langtang-Lirung Peak collapsed, sending huge amounts of ice, rock and debris

crashing into the valley below. The U.S. Geological Survey estimates more than 100

million cubic meters of material was displaced. That's the equivalent of 40,000 Olympic-sized

swimming pools