What we know about deadly Nepal-Tibet floods

Updated 1 hour ago.

Key points

• The Nepal Tourism Board remarked on Thursday that 644 tourists are still missing, 33 of which are UK nationals.
• Smaller numbers of travellers from South Korea, South Africa, Portugal, the Netherlands and New Zealand are additionally among the missing.
• China's state broadcaster CCTV remarked on Thursday that the number of residents missing in the mudslide disaster in Tibet's Gyirong county had risen to 558.
• UK Prime Minister Andy Burnham remarked the British administration would do "everything we can" to backing British nationals in Nepal.
• In neighbouring India, Prime Minister Narendra Modi remarked his administration was "prepared to provide Nepal with all possible types of humanitarian assistance".

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. While Nepalese office-holders anticipate "huge scale loss", chinese state media has remarked there are significant casualties. Here is what we know so far. What caused the deadly landslide?

Nepal's foreign minister initially remarked an earthquake was noted on the Tibet-Nepal border shortly before the landslide, suggesting it may have triggered the disaster.

Meanwhile, the United States Geological Survey (USGS) had first documented the event as a magnitude 4.4 earthquake on Wednesday, but afterwards 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 remarked on Thursday.

Earlier Nepali authorities had additionally informed the BBC that a massive chunk of ice may have collapsed from a mountain, pulling down rocks and other sediments with it.

As rescue efforts continue, scientists are trying to piece together the exact order of events, climate change is known to be driving faster glacier melt in the Hindu Kush Himalaya region and.

Simon Cook, senior lecturer in energy environment and security at the University of Dundee who specialises in glaciology, remarked "climate change could have an impact".

He informed 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.

As well as data on recent rainfall, 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.

In practice, 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.

As residents fled the fast-moving wave of material in the Nuwakot region, footage indicated a wall of mud and rock sweeping away buildings, roads and vehicles.

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 documented along the Bhote Koshi, Trishuli and Narayani rivers.

Deaths have additionally been noted in villages on the Tibetan side of the border.

Meanwhile, the International Centre for Integrated Mountain Development (ICIDMOD) has cautioned secondary flooding could occur over the next few days as of the debris that washed into the river systems.

In a report, the ICIDMOD remarked 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. How plenty of residents are dead and missing? The number of individuals killed or missing is still becoming clear.

Nepali police say at least 270 individuals have died. Among those killed, 64 were discovered in downstream areas in the Chitwan district while another 26 were identified in Nawalparasi East.

In an update on Thursday morning, Nepal's National Disaster Risk Reduction and Management Authority remarked 826 residents are still missing, including more than 529 tourists, with 466 foreigners among them.

Meanwhile, China's state broadcaster CCTV remarked on Thursday that the number of residents missing in the mudslide disaster in Tibet's Gyirong county had risen to 558.

Among these are 260 foreign nationals, CCTV remarked, adding that the death toll remained at three.

Meanwhile, the Nepal Tourism Board remarked on Thursday that 644 tourists are still missing, 33 of which are UK nationals.

It is not clear if any of the missing in the Nepali and Chinese figures have been counted twice.

For context, the border at Gyirong is the main crossing point for tourists and traffic between China and Nepal. How are governments responding?

Nepal's prime minister remarked "the entire nation has been left shocked and deeply distressed" and that office-holders would coordinate with China on the response.

China's President Xi Jinping pressed an "all-out" search effort, and promised stronger monitoring and early warning systems to prevent secondary impacts.

UN Secretary General António Guterres notes he is "saddened by the severe flooding", adding that UN teams and partners are mobilising supplies and personnel in Nepal to backing the government-led response.

Meanwhile, the US has promised $500, 000 (£367, 982) in aid which will be applied to cover emergency shelter, water, sanitation and other relief items for communities affected by the floods.

UK Prime Minister Andy Burnham remarked the British administration would do "everything we can" to backing British nationals in Nepal. What countries are the missing tourists from?

Tourists from all over the world come to Nepal for its mountains and sacred sites. Official figures suggested at least 291 foreigners are among the missing, including.

Taken together, the developments around what we know about deadly Nepal point to a situation that is still moving, and the coming days should bring more clarity.