How a glacier collapse triggered a deadly landslide and flooding along the Nepal-China border

Meanwhile, the lower part of this glacier. Onto the valley floor.

Key points

• > <!–> [–> Rescuers continued searching for survivors in the debris-strewn valleys and hillsides of Nepal on Thursday while more than 1, 000 individuals remained missing there. <!–>.
• > <!–> [–> "It was a huge gush of mud coming straight towards us, " remarked Keshav Prasad Baral, ⁠a 68-year-old survivor being treated in a Nepali hospital. <!–>.
• <!–> [–> Satellite images compare a Himalayan glacier before and after the landslide, with a size comparison to Dubai's Burj Khalifa.
• > <!–> [–> The mudslide slammed into Gyirong port in Tibet and into Nepal, creating high-speed flash floods that washed away entire roads and power projects and inundated villages. <!–>.
• Sources: NASA/USGS SRTM Digital Elevation Model; Google Earth.

Meanwhile, the lower part of this glacier. Onto the valley floor. An avalanche of ice and rock. Swept down the valley. In practice, the massive landslide caused.

<!–> [–> Aerial 3D terrain view of Nepal's Langtang valley, snow-capped peaks below Langtang Lirung, with orange arrows tracing three stages: a glacier's lower section collapsing, an ice-and-rock avalanche and debris flow sweeping down, then catastrophic flooding. <!–>.

<!–> [–> T he rapid landslide of ice and rock and flash floods that killed hundreds in Nepal and China's Tibet were triggered when the lower part of a glacier broke off and crashed on to the valley floor hundreds of metres below. <!–>.

> <!–> [–> It is not clear what caused the glacier to collapse. Nepali authorities initially pointed to an earthquake in the region as a possibility, but the U.S. Geological Survey afterwards stated the documented tremor was in fact seismic energy generated by the collapse of glacial rock and ice, followed by debris flow. <!–>.

> <!–> [–> Satellite imagery demonstrates a substantial part of a glacier near Langtang Lirung peak split off when compared with imagery taken a few days earlier. <!–>. August 26 After the landslide. August 24 Before the landslide.

<!–> [–> Satellite images compare a Himalayan glacier before and after the landslide, with a size comparison to Dubai's Burj Khalifa. An Aug 24 Sentinel-2 view labels the glacier terminus at 5, 200 m altitude, and an Aug 26 Landsat 9 view demonstrates landslide debris where the glacier broke. <!–>.

<!–> [–> An avalanche of ice and rock swept down the Lhende Khola river. It runs along the mountainous Nepal/Tibet border. <!–>.

> <!–> [–> Verified videos indicated dozens of residents swept away at the border. <!–>.

> <!–> [–> Chinese administration geologist Guo Zhaocheng stated the ice-avalanche debris flow that caused the mudslide travelled at regarding 50 metres (165 feet) per second, leaving residents little time to react, and extended for more than 20 km (12 miles). <!–>.

After a descent of more than 4, 500 metres (14, 763 feet) in elevation from the Himalayas. <!–>, <!–> [–> Flood waters created by the collapse rushed through valleys in Nepal and altered river channels more than 100 km (62 miles) downstream, near the Indian border. 5, 127 m Approximate elevation of glacier collapse. Sources: NASA/USGS SRTM Digital Elevation Model; Google Earth.

<!–> [–> Elevation profile and terrain map tracing the Trishuli River over 100 km from a glacier at 5, 127 m in China, where a collapse began, steeply down past Timure, Syapru Besi, Hakubesi, Betrawati, Trishuli and Devighat to Kolpurtar in Nepal below 500 m. <!–>.

<!–> [–> The Red Cross remarked that entire villages had been destroyed and impassable roads and bridges had left communities cut off. The full scale of the disaster remains unclear, it continued. <!–>.

> <!–> [–> "As it obtained closer, it kept rising higher and higher. When I saw it enter our home, I tried to grab my wife's hand and take her to the terrace. But she was swept away by the mud." <!–>.

]–> <!–> [–> The International Centre for Integrated Mountain Development remarked on Wednesday the flash flood sent a powerful surge of water, sediment and boulders through the Bhote Koshi and Trishuli river systems, adding that water levels on the river at the Galchhi area downstream reportedly rose by as much as nine metres (30 feet) within 30 minutes. <!–>.

<!–> [–> A grey terrain map traces the blue Trishuli River from a glacier in Nepal's mountains. Satellite images of Syapru Besi, Betrawati and Devighat with yellow dots marking hundreds of buildings inside the debris flow path. <!–>.

<!–> [–> "Climate change is generating conditions that can destabilise high-mountain rock and ice, " remarked Simon Cox, chief scientist at the Mountains to Sea programme at Earth Sciences New Zealand. <!–>.

> <!–> [–> That in turn makes collapses and cascading hazards of the kind seen this week more frequent, he continued. <!–>.

> <!–> [–> While experts caution against describing climate change as the sole, immediate trigger for Wednesday's collapse, they say that rising temperatures and melting glaciers probably played a role in the disaster. <!–>.

> <!–> [–> Warming can reduce ice backing on steep slopes, boost meltwater, and change patterns of freezing, thawing and rainfall. It can weaken mountainsides and produce sizeable collapses more probable in some spots, Cox continued. <!–>.

> <!–> [–> Nepal and China both cautioned on Thursday of fresh risks of flooding in the Himalayas as two lakes that have developed on either side of their border threaten to burst in a region still grappling with ‌this week's catastrophic flood. <!–>. [–> <!–> [–> Satellite image via Google © 2026 Landsat / Copernicus, Airbus <!–>. [–> <!–> [–> Edited by <!–>. [–> <!–> [–> Jon McClure, Rebecca Pazos, Simon Scarr <!–>.

In short, how a glacier collapse triggered a deadly landslide and flooding along the is the central thread here, and readers can expect follow-up reporting as the picture becomes clearer.