Jacob Phillips
Live reporter

Image source, Reuters

A flooding expert warns that the immediate concern in Nepal and Tibet is that the flash floods have created new risks.

Jeff Da Costa, researcher in flood early warning and disaster risk at the University of Reading, tells me that debris from the disaster has blocked rivers and formed new lakes upstream.

Similarly, infrastructure in the area is seriously damaged, meaning that "a second flood does not have to be as large as the first to cause serious impacts," he says.

Da Costa says monitoring how lakes and barriers in the area are changing and tracking where they may burst "now matters enormously".

The researcher adds it is important for China and Nepal to share monitoring information as "what happens upstream can affect people across the border very quickly".

"Information has to move just as quickly and lead to practical decisions on the ground," he adds.

Da Costa also describes how climate change is important background context for the disaster because warming is changing glaciers, permafrost and slope stability across the Himalayas.

But he says the disaster can not be attributed to climate change without further analysis.

Simon Atkinson
Australia reporter

The sister of an Australian man missing in Nepal say they are "holding onto hope while also trying to prepare our hearts for whatever comes".

Michael Keats, an outdoor educator from New South Wales, was initially thought to be away from the disaster zone, but relatives later learned he was at the immigration centre at the Nepal-Tibet border when the tragedy hit.

His sister, Karen Hayley, describes him as "the absolute light of our lives" and says he was travelling through Nepal "as part of a deeply significant spiritual pilgrimage to Mount Kailash".

"This was a journey Michael had planned, dreamed of and longed to experience for a long time," she wrote on Instagram.

"Although we are painfully aware that Michael’s chances of survival may be slim our family is still desperately waiting for answers."

She adds the family are "holding onto hope while also trying to prepare our hearts for whatever comes".

Laura Bicker
China correspondent

Image source, VCG via Getty Images

Tibet, which China annexed in the 1950s, is one of the most strictly controlled regions in the country.

It has long demanded greater autonomy and is heavily monitored because Beijing fears any signs of instability such as protests.

That is why orders have come personally from the top leader Xi Jinping and why Premier Li Qiang visited the site on Thursday. It is rare for him to make a visit so soon after a major disaster.

To get into Tibet requires a special visa and it is difficult, if not impossible, for foreign media to gain entry. Trying to contact people there is just as hard.

This makes it very difficult for us to know what is happening and we are relying heavily on reports from Chinese state media.

Pilgrims making their way from Nepal through Tibet to the sacred mountain of Mount Kailash need four separate permits, which includes special permission from the Chinese military.

Laura Bicker
China correspondent

As we've just reported, rescue teams on the Tibetan border have been moved to safety after a drone monitoring the region spotted yet another landslide.

Reports from state media, citing China’s Ministry of Emergency Management, said a monitoring drone had detected the landslide downstream of a lake which has been formed within the rubble and debris.

This has now formed a second so-called barrier lake.

These bodies of water are being assessed by experts, according to the state broadcaster’s report.

Fears of flooding from the lake have already sparked panic on both sides of the border earlier this week. On Friday, ice and snow fell from the mountain and into the lake causing it to overflow.

Experts in China have been monitoring its levels since then and have set up observation posts to raise an alarm should it overflow.

A new lake has formed in Tibet after a landslide occurred downstream of the existing barrier lake, Chinese state media says.

A barrier lake is a body of water formed when debris dams up a river. An existing barrier lake, which formed in the aftermath of the flash floods, had reportedly been depleting naturally following concerns it could result in more flooding.

Chinese Central TV (CCTV) says a monitoring drone detected a landslide on Saturday, which then resulted in debris forming a new blockage and a new barrier lake.

The landslide is reported to have occurred about 2.8 kilometres (1.7 miles) downstream of the barrier lake on the Pruqpu Qiang Zangbu River.

China's Ministry of Emergency Management quickly gathered experts to assess the situation and rescuers near the Gyirong Port have been moved to a safe location, it adds.

As we reported a short while ago, Nepal's disaster agency says the death toll in the country has jumped to 734, up from the 675 reported yesterday.

In the last hour, Nepal's Police also reported that 734 bodies have been recovered.

It also shared the following figures:

• Missing: 2,498
• Rescued: 8,186
• Injured: 242 (includes some who have been discharged)
• Security forces deployed: 19,895

Image source, Getty Images

If you're just joining us, here is what you need to know as rescue operations in the Nepal-Tibet border area hit by a deadly flash flood enters the fifth day:

• Officials in Nepal say 734 people have been confirmed dead following flash floods on Wednesday, up from the 675 reported yesterday evening
• Chinese state media report that the death toll in Tibet has risen to 16 - here's why it has been harder to assess the scale of the disaster in Tibet
• Nepal counts more than 2,400 people missing while China has reported 546 missing, including 261 foreign nationals

• Aid has been arriving, but rough terrain and rains are making delivery extremely difficult, according to the UN
• Rescuers in Nepal working through the night on Saturday are battling adverse weather in their efforts to reach workers trapped in hydroelectric tunnels in flood hit areas
• Nepal's disaster response agency has received reports of a flood level increase near the Bhote Koshi River, one of the two rivers through which the initial debris flow travelled on Wednesday. It has asked people to stay alert in areas around the river

Laura Bicker
Reporting from Beijing

Image source, Getty Images

As we reported earlier, authorities in China say 16 people have been confirmed dead and more than 540 remain missing in Tibet.

Chinese state media said that among the 546 people missing after Wednesday’s landslide, 261 are foreigners from 23 countries - including 15 British nationals.

Search and rescue teams are still combing through the mud and debris at the border but have so far found no survivors.

Gyirong Port is the main crossing point for tourists trekking from Kathmandu to the sacred Mount Kailish in Tibet.

Meanwhile the danger posed by a lake which formed amid the landslide debris appears to have subsided for now, however authorities say there is still a continued risk of further mudslides and have set up monitoring stations to alert rescue teams along the border.

Azadeh Moshiri
Reporting from Kathmandu

The forecast suggests the rain will continue until at least Monday, adding to an already challenging search and rescue operation.

Many remain trapped in hydropower tunnels in northern Nepal, and thick mud is blocking rescuers from entering them.

India and China have both sent experts to help. With hundreds of foreign nationals missing, aid is continuing to pour in.

The United States has pledged $3.6m in humanitarian assistance, while the United Kingdom has sent a rapid deployment team to Nepal to support British nationals.

This is Nepal’s worst disaster in more than a decade. Scientists believe the flash flood was triggered by a “glacial collapse", when all or part of a glacier disintegrates, and led to “catastrophic impacts downstream".

Despite the scale of the disaster, thousands of people have been rescued.

But as the search enters a fifth day, many of the families we meet tell us they’re preparing for the worst.

The death toll in Nepal has risen to 734, the country's disaster management agency says.

Image source, Getty Images

Aid is arriving but it is proving difficult to reach the people affected, United Nations resident coordinator in Nepal Lila Pieters Yahia tells the BBC.

The UN coordinator says both Indian and Chinese rescue teams that arrived yesterday were working to provide extra support.

"But it's difficult to bring it to reach the people because the access is extremely difficult," Yahia says.

The government has begun "airlifting everything" by helicopter, and using drones to deliver the aid more effectively is being discussed within the government, the official adds.

"The weather is not helping us," Yahia adds.

As we reported earlier, a rainfall warning is in effect in the disaster zone until Monday.

Navin Singh Khadka
Environment correspondent, BBC World Service

How much of a role climate change played in the collapse of the glacier that caused this devastating flood might be known if there are focused studies in the days to come.

But what we already know is that global warming has led to accelerated melting of Himalayas' glaciers, icefields, snowpacks and permafrost.

Scientists say thinning and retreating of glaciers can not only cause their collapse but can also rapidly fill up glacial lakes that can then burst out causing floods.

They say ice and snow buttress mountain slopes – just like cement keeps buildings intact. When they fast melt, then mountains destabilise and we see increased incidents of rockfalls, landslides, avalanches and debris floods – as we are seeing in the Hindu Kush Himalayan region.

Because of warming, experts say, higher parts of mountains now also see rains instead of snow that can also make them unstable.

A study by the International Centre for Integrated Mountain Development released in March showed that ice loss rates in the region have doubled since 2000.

Image source, Getty Images

Heavy rain since the flash flooding first hit on Wednesday has made search and rescue efforts more challenging, authorities say.

And the forecast for the area suggests the wet weather will continue.

The Nepalese Department of Hydrology and Meteorology has issued yellow rain warnings for the area lasting until at least Monday, advising people to stay updated.

That's the lowest of the three warnings the agency issues - below amber and red - and is fairly typical for the area. But it will likely further hamper efforts on the ground.

Drone video captures moment of glacier collapsepublished at 03:24 BST 30 August

03:24 BST 30 August

By Charlotte Green and Benedict Garman

BBC Verify has authenticated two videos which show the moment of a glacier collapse in the Himalayas which triggered the deadly Nepal-Tibet floods.

The videos, filmed by a drone and posted to the Chinese social media platform Xiaohongshu, capture the landslide near the Langtang Lirung peak, more than 7,200m (23,600ft) above sea level.

Plumes of dust can be seen rising into the air near the snow-covered mountains.

The location of the clips match the direction of the floodwater which surged down the Trishuli river, devastating villages and communities along its way.

Simon Atkinson
Australia reporter

Chinese state media is reporting that there are six Australians among the 261 foreign nationals identified as missing on the Chinese side of the border between Nepal and Tibet.

I am trying to establish whether the Australian government believes that those six are among the total of 41 citizens unaccounted for (the national broadcaster the ABC says it understands this has risen to 42 but I have not yet verified this).

One of those missing is Sumi Adhikari from Sydney. This morning I've been in touch with her husband Nava Pandey, who has travelled to Nepal to try and help locate her.

He is asking for "close coordination between the Nepalese and Chinese authorities".

"We respectfully call upon the Chinese government and local authorities to release all available verified information, provide regular updates about the search efforts and establish direct communication with the affected families," Pandey says.

"Families should not be left without answers during such a critical time."

Image source, Supplied

As I mentioned in a post yesterday, also missing from the same tour group is Reshma Patel from Newcastle in New South Wales.

Her husband Bhavin Patel has also flown to Nepal and in a statement says that phone data had led him to believe his wife had crossed into Tibet.

"We respectfully appeal to Australia, Nepal and China for urgent coordination and continued search efforts in the Gyirong area," he wrote.

"Our family is desperately seeking assistance to locate her".

According to Chinese state broadcaster CCTV, 261 foreigners from 23 countries are among the 546 missing people in the Tibet flood.

Chinese authorities have notified their embassies and consulates in China, CCTV reports.

Fifteen British nationals are among the missing in Tibet, according to the report.

Nepalese authorities have already reported that 33 British nationals are missing. Several of them are thought to have been making their way across the border to Tibet, so it is unclear how many of the 15 British nationals reported as missing by Chinese authorities are included in the figure reported by Nepal.

Here is a further breakdown of missing foreigners on the Tibet side, according to Chinese state media: three Malaysians, 104 Nepalis, 49 Indians, four South Africans, two Irish nationals, two Estonians, three Germans, three Russians, two French nationals, one Finn, two Dutch nationals, 33 Latvians, one Lithuanian, one Portuguese national, one Ukrainian, one Spaniard, one Hungarian, six Canadians, 18 Americans, six Australians and two New Zealanders.

The information on the missing people came from a joint investigation and collaboration between multiple agencies including foreign affairs, public security, culture and tourism and emergency management.

Members of the military and police are among those who are continuing to search for the hundreds of people still missing in both countries.

Image source, Getty Images

Image source, Getty Images

Image source, Reuters

Image source, Getty Images

According to Chinese state broadcaster CCTV, as of 18:00 local time (11:00 BST) Saturday, 16 people had died from the mudslide in Gyirong county, Shigatse city, while 546 others are missing.

Previously officials had said seven people had died.

At a news conference in Gyirong County, officials said the mudslide had caused significant casualties at the Gyirong border port.

Nepal's National Disaster Risk Reduction and Management Authority (NDRRMA) says it has received reports of a flood level increase near the Bhote Koshi River.

This was one of two rivers through which powerful flood water and debris travelled on Wednesday, rushing past popular tourist and pilgrim towns in northern Nepal.

The NDRRMA says people should stay alert in the areas around the river.

Initial reports of an earthquake on the Nepal-Tibet border led many to believe that a tremor had caused a landslide, which in turn caused the devastating floods early on Wednesday.

However, the US Geological Survey (USGS) later confirmed the disaster was caused by a "glacial collapse", which is when a glacier or part of a glacier disintegrates.

The impact of the collapsed glacier hitting the bottom of a valley was so powerful that it registered a magnitude of 5.2, according to the agency, causing "subsequent catastrophic impacts downstream".

Powerful floodwaters and debris travelled some 62 miles (100km) downstream from the Trishuli and Bhote Koshi Rivers, the USGS said, careering through towns popular with mountaineering tourists and pilgrims in northern Nepal.

The International Centre for Integrated Mountain Development (ICIDMOD) has warned secondary flooding could occur in the coming days as a result of debris that washed into the river systems.

The ICIDMOD said they were assessing whether the Trishuli River had been temporarily blocked in narrow sections. If this is the case, it is at risk of forming a landslide dam and a second flood.