Rescue operations have resumed after a brief pause, but experts caution of danger from a newly formed lake.
Rescuers have resumed efforts in the flood-ravaged Nepal-Tibet border region after a brief pause over fears of a second glacial flood, as the death toll rose to 633 and the number of people missing neared 3,000.
Nepal’s police said the number of people killed in the disaster has risen to 626 on Saturday.
The country’s disaster authority reported the total number of people missing on its side of the border to 2,426, of which 517 are foreigners – which could include tourists as well as foreign workers.
Chinese authorities have reported that the death toll in Tibet has risen to at least seven, with 554 people missing.
Al Jazeera’s Minelle Fernandez, reporting from the Nepalese capital, Kathmandu, said the government has requested specialist help from India and China to “fill gaps” in its rescue operations. Those teams, which includes tunnel rescue, are expected to arrive later on Saturday.
“The reason the [Nepalese] foreign ministry spokesman said that this decision has been taken is because lives are at stake and that it is very, very urgent,” she said.
“The reason that initially Nepal had said they didn’t want assistance is they didn’t want the chaos which comes with huge teams being fanned out in different areas.”
The catastrophe began on Wednesday morning when part of a glacier collapsed at roughly 5,200 metres in the Himalayas, plunging about 1,200 metres and gathering rock and debris before slamming into the Lende River.
The resulting surge swept south through Nepal’s Rasuwa, Nuwakot and Dhading districts, at one point raising the Trishuli River by 9 metres in 30 minutes. The US Geological Survey revised its initial finding of an earthquake trigger, concluding the seismic signal instead came from the landslide itself.
A new lake formed at the collapse site and began rising afterwards, prompting a temporary halt to search efforts amid fears of a second flood. Operations have now resumed after the lake’s risks were deemed manageable.
Alton Byers, a glacial-hazards scientist at the University of Colorado Boulder’s Institute of Arctic and Alpine Research, told Al Jazeera that the barrier holding back the new lake is highly unstable, made up of loose debris that had cascaded into place two days earlier, and that there is “not much holding it”.
Byers said the safest outcome would be a natural, gradual drainage, noting that Chinese crews could also try to lower the lake using hand tools and other methods manually – a technique he said has been used in other countries prone to glacial lake outburst floods.
Chinese Premier Li Qiang visited the disaster zone in Gyirong on Thursday, and President Xi Jinping chaired a meeting ordering officials to “scientifically formulate search-and-rescue plans” and strengthen monitoring of glacial lakes, according to state media.
International aid has arrived from India, the UN, the Red Cross Federation, Australia, South Korea and the US. Officials warn the death toll will likely keep rising as rescuers reach areas still cut off by mud and washed-out roads.