ネパールとチベットの国境付近で氷河崩壊による大規模な鉄砲水が発生し、165人以上が死亡

At 8.37am on Wednesday, an enormous section of a glacier in the Himalayas sheared free and crashed on to the valley floor in Nepal’s Langtang national park, about 60km north of the capital Kathmandu, near the mountainous Nepal-Tibet border. Such was the force of the event, it was initially reported as a magnitude 4.4 earthquake. The United States Geological Survey later determined the tremor was caused by glacial rock and ice collapsing, registering a magnitude of 5.2.

The collapse triggered a huge release of water, mud, rock and ice that thundered down valleys and swept down the Lhende Khola, Bhote Koshi and Trishuli rivers. The high-speed flash floods careered towards northern Nepalese towns, including areas popular with mountaineering tourists and pilgrims. Horrifying videos from the Gyirong border post, which connects Nepal and Tibet, showed people running for their lives as the wall of debris obliterated buildings and swept away lines of buses. In Nepal, houses and roads were washed away in seconds.

小型病院で治療を受けていた68歳の生存者であるケシャブ・プラサド・バラル氏は、大量の泥が自分たちめがけてまっすぐ押し寄せてきたと述べ、それが近づくにつれてどんどん高さを増していったとし、自宅に入ってきたのを見たときに妻の手をつかんでテラスに連れて行こうとしたものの、妻は泥に押し流されてしまったと語り、4、5時間後にヘリコプターが救助に来てくれたが、妻はまだ泥の下のどこかにいて、もう帰らぬ人となったと述べた。また別の生存者は、自分が働いていた家が消えていくのを見つめながらマンゴーの木にしがみついて助かったと語った。

In a stark illustration of the deluge’s deadly power, a bridge crossing the Trishuli river was shown in a video being washed away in a tsunami-like flood. Multi-level homes were quickly submerged as the torrent gouged through the riverside town. Bibek Kumal, a Nepali labourer, was working in Bidur when others sounded the alarm. カトマンズの国立外傷センターのベッドから、クマル氏は走り出したところ、まるで地震のように水壁が轟音を立てながら押し寄せてきたと語った。

Massive landslides and flash floods on the Nepal-Tibet border have caused widespread damage and left hundreds dead or missing. Search and rescue operations are under way. Chinese state media has said there are significant casualties, while Nepalese officials anticipate "huge scale loss". Nepal's foreign minister initially said an earthquake was reported on the Tibet-Nepal border shortly before the landslide, suggesting it may have triggered the disaster.

The United States Geological Survey (USGS) had first reported the event as a magnitude 4.4 earthquake on Wednesday, but later confirmed the incident "was instead a glacial collapse and debris flow" that "caused subsequent catastrophic impacts downstream". "Additional analysis of nearby seismic stations, long period seismic waves, and satellite imagery led to the determination that the seismic event was instead a glacial collapse and debris flow, and that no earthquake had occurred," USGS said on Thursday. Earlier Nepali authorities had also told the BBC that a massive chunk of ice may have collapsed from a mountain, pulling down rocks and other sediments with it.

Climate change is known to be driving faster glacier melt in the Hindu Kush Himalaya region and, as rescue efforts continue, scientists are trying to piece together the exact order of events. Simon Cook, senior lecturer in energy environment and security at the University of Dundee who specialises in glaciology, said "climate change could have an impact". He told the BBC "permafrost is partially holding some mountainsides together, this permafrost is warming and thawing and degrading so you are going to get more landslides". One possibility is that water from rainfall or melting ice may have destabilised the ground or ice, triggering a chain reaction. Scientist will be looking at satellite images of exactly where the landslide occurred, whether any glacial lakes suddenly drained, and where the river might have become blocked, as well as data on recent rainfall.

A deluge of material careered towards northern Nepalese towns, including areas popular with mountaineering tourists and pilgrims. The border is around 40 miles (64.4km) north of Nepal's capital city Kathmandu. Footage showed a wall of mud and rock sweeping away buildings, roads and vehicles, as people fled the fast-moving wave of material in the Nuwakot region. In one video, a towering wall of water and mud was seen rushing down a gorge along the Trishuli River and enveloping the Rasuvagadhi Border check point, a multi-storey building. Severe flooding has been reported along the Bhote Koshi, Trishuli and Narayani rivers. Deaths have also been reported in villages on the Tibetan side of the border.

In Tibet, China has ordered "all-out" rescue and relief efforts. Rescuers are struggling to reach the disaster zone after more than 160 people were killed in Nepal in a massive flash flood and mudslide. Hundreds of tourists are missing, including more than 100 from India, 54 from the US, 34 from Australia, and 33 from the UK, as well as more than 100 from Nepal itself, according to officials. The area is popular with pilgrims and trekkers. Experts warn that debris in a river near the disaster zone could trigger a second flooding event. The US, China, the EU and India are among the countries that have pledged assistance or dispatched relief supplies.

Dozens of Nepalese police officers and army personnel are also missing, as well as power workers. Authorities initially thought an earthquake may have preceded the flooding – but the US Geological Survey now says the "seismic energy was instead generated by a landslide". The International Centre for Integrated Mountain Development (ICIDMOD) has released a detailed assessment of what happened on Wednesday, when a major flash flood caused devastation in Nepal and Tibet. In it, experts warn of a secondary potential flooding event, as a result of the debris that washed into the river systems.

The experts cited in the report say they are in the process of assessing whether the Trishuli River has been temporarily blocked in narrow sections. If it has been blocked, it is at risk of forming a landslide dam – and a second flooding event. Authorities and scientists are continuing to evaluate the size, location and stability of any potential blockages. The Nepali army has deployed 2,000 military personnel for land and aerial search and rescue operations in flood affected areas. The troops are concentrated in the worst-hit areas, including the Rasuwa and Nuwakot districts, army spokesman Brigadier General Rajaram Basnet told the BBC. The military has thus far managed to rescue 97 people trapped in floods, he said, noting that three of them were workers stranded in the tunnel of Trishuli A hydropower project. Nepal's police and the armed police force have also deployed officials to help with search operations.