Experts zero in on likely cause of deadly Nepal mudslide, with more than 1,300 missing

The catastrophic floods in Nepal and Tibet that have killed at least 273 people were triggered by a massive glacier collapse and debris flow that registered as a magnitude 5.2 landslide, according to the U.S.

Geological Service (USGS).

The USGS originally pinpointed the cause of the mudslides as a 4.4 magnitude earthquake but later updated its analysis after observing data from nearby seismic stations, long period seismic waves and satellite imagery.

That data suggested that no earthquake had occurred.

Climate experts at the Kathmandu-based International Centre for Integrated Mountain Development told The Associated Press that Wednesday’s flash floods were likely triggered by a glacial avalanche.

"Hydrological observations indicate the exceptional speed and magnitude of the flood wave," they said in a statement, adding that at one point, the water levels on the Trishuli River rose by as much as 27 feet in just a half hour.

TERRIFYING VIDEO CAPTURES PEOPLE FLEEING INCOMING MUDSLIDE AT NEPAL-CHINA BORDER Rescue teams are now searching for the more than 1,300 people who went missing during the floods along the Nepal-China border.

Many of them were foreigners and pilgrims.

Nepal Police on Thursday began posting lists of Nepali and foreign nationals missing.

Several dozen Americans were listed.

Dozens of bridges were destroyed and nearly 25 miles of roads were damaged, hampering search and rescue efforts, according to Nepalese officials.

The Nepalese army rescued more than 100 people from flood-hit areas by helicopter Thursday morning, according to army spokesperson Brig.

Gen.

Raja Ram Basnet.