TL;DR

Hundreds of Trekkers Missing in Nepal Flooding

Equations
1. Potential Energy of 1 kg of water at height
E = m g h --> mass 1 kg, g = 9.81 m/s/s, h = 1200 m ( Assuming 1200m as height, and not glacial path length )
E = 11.8 kJ

Temperature rise of 1 kg water from heat addition Q

Edit:
dt = Q / ( m Cp ) Q = 11.8 kJ, , = 1 kg, Cp = 2.050 kJ / ( kg C )
dt = 5.76 C

I would take the

Reaching warmer temperatures along the path 50 km further down the valley, all of the slush would become water.

You might want to factual check for sensationalism in this one paragraph:

View attachment 373873

[Mentor Note: Some AI content has been deleted out of this post since the thread is in the technical forums]

Equations
1. Potential Energy of 1 kg of water at height
E = m g h --> mass 1 kg, g = 9.81 m/s/s, h = 1200 m ( Assuming 1200m as height, and not glacial path length )
E = 11.8 kJ

Temperature rise of 1 kg water from heat addition Q
dt = Q / ( m Cp ) Q = 11.8 kJ, , = 1 kg, Cp = 2.050 kJ / ( kg C )
dt = 5.76 C

The chunk of ice would have risen in temperature of 5.76 degrees C from the drop.

And then there is the phase change to water, as you have expressed.

Post #3 edited

Satellite image at the 1:42 mark.

1. Question of where all the water came from.
2. Blocked lake upriver posing a risk of secondary water cascade
3. Seismic recordings were that of the deluge ( not an earthquake in the normal sense )

If the mass of the glacier that fell is estimated to be 5 000 000 000 kg from 1200 m then v =153 m/s. And with KE = 1/2 mv^2 . joules at impact= 58x10^9. The phase change from ice to water=334000 joules/kg. So only about 173,653 kg of ice converted to water at impact.

[Mentor Note: Some AI content has been deleted out of this post since the thread is in the technical forums]

Affected districts/towns/villages: Nuwakot, Nepal; Rasuwagadi, Nepal - Gyirong, China (Tibet) border crossing; Dhading, Nepal; Chitwan, Nepal

Floods kill more than 500 people in Nepal and Tibet, with 90 Americans [and 30 Canadians] among the missing
https://www.npr.org/2026/08/27/nx-s1-5946309/nepal-tibet-deadly-floods

https://abcnews.com/International/h...issing-massive-nepal-tibet/story?id=136022919

Bhotekoshi River Flood Devastates Rasuwa, Nuwakot, Dhading, and Chitwan
https://english.ratopati.com/story/...floods-sweep-away-settlements-increasing-fear

Apparently, there is also flooding in Gyirong county, China.

Multi-story buildings (looks like ~20 m) overtopped by flood (mudslide with rocks) at Nepal-China (Tibet) border checkpoint. It looks like a 5 or 6 story building south (downstream) was inundated. I would guess the water/mud/rock flood was perhaps 30+ m.

https://en.wikipedia.org/wiki/Langtang_Lirung
https://en.wikipedia.org/wiki/Tsangbu_Ri

https://phys.org/news/2026-08-satellite-images-bedrock-glacier-collapsed.html

https://www.cnn.com/2026/08/28/worl...lirung-peak-nepal-china-flood-hnk-vrtc-digvid

Prof. Steiner from U of Graz mentioned a similar event happened last year (2025) in the same location!

Other sources point to glacier on the north side of Langtang Lirung.
https://www.bbc.com/news/videos/c07l9ggx8m7o

https://www.reuters.com/graphics/NEPAL-FLOODS/MAP/byvrdywwlve/

Update/Edit - Graph shows Lende Khola and Bhote Koshi Rivers merge at Rasuwagadi, Nepal - Gyirong, China (Tibet) border crossing and the outflow is the Trishuli River

After a year stuck in the ice, the Shackleton Antarctic expedition dispatched enclosed lifeboats to beg for rescue at a distant island. On the way they sighted what they at first believed to be mountains in the distance but was actually an enormous wave. It must have shaken them like the seeds in a maraca. The crew survived but they said after that Shackleton was never again quite the same.

Scientists denied the existence of such waves until one was recorded at an oil platform in the North Sea.

The largest wave that attracts surfers is in Portugal. The impact of the falling water can be so great that the falling wave bounces off of the surface. The mass bounces so high that it bounces again. And again for a total of three times. A surfer was struck upward by the first rebound, which broke his back. He survived. This is not the most dangerous surfable wave.

I have not yet found the video except for a facebook post. There is water in the river (ostensibly from melt water), which is probably a meter or so in depth, but the flood upstream would be collecting that water and carrying it downstream.

Meanwhile, some other videos:

The flood knocks down buildings build along the river bank, so one would conclude that the locals probably never experienced such flooding in recent memory, otherwise it would be insane to build a structure (home or otherwise) in a flood plain subject to such catastrophic flooding.

Edit/update: I just watched a video in which the commentator/presenter mentioned the flood was up to 30 m high and traveling at up to 75 km/h. Teacher(s) rapidly evacuated 1643 students from Tribhuvan-Trishuli Higher Secondary School (in Trishuli Bazar, Nepal) and took them to higher ground as the flood approached. The three story school buildings have been obliterated!

The first accounts, including from the U.S. Geological Survey (USGS), indicated the event was a magnitude 4.4 earthquake, which might have shaken rock and ice loose in a landslide that sparked the flood. A dam break was also touted as a possibility. But within 15 minutes of waking up, Cook, who has been conducting research on the Lhende Khola, had downloaded publicly available seismic data from a Nepali station located north of Kathmandu to see for herself. “I could already see that some of the initial attribution was wrong,” she says. Rather than the quick, intense seismic jolt typical of an earthquake, the data showed low-frequency, long-period waves characteristic of prolonged rumblings: a giant landslide, which itself generated the seismic signal.

On the opposite side of the Atlantic Ocean from Cook, Ekström was using data from the Global Seismographic Network, a collection of about 200 seismometers operated by many countries, to come to the same conclusion. He fed the seismic data into algorithms developed at Lamont-Doherty to find that a more accurate magnitude was 5.7—equal to a significant earthquake. It soon became “clear that [the Lhende Khola landslide] was one of the largest in the last decade or two in the world,” he says.

Cook, Ekström, and a smattering of other top natural hazard researchers soon created a Slack group to share data, discuss interpretations, and argue. (As of this publication, the group has more than 85 scientists.) It was here that the next useful observations got shared: satellite imagery from Planet Labs, which takes daily images of Earth’s surface at a resolution of 3 to 5 meters. But there was a problem: In the few available images of the mountains where the seismic signal originated, there were “very strategically placed inconvenient clouds,” Cook says. What could be clearly seen was a sharp edge, at about 5200 meters above sea level, where a glacier that blanketed the mountain had snapped off.

The imagery soon led to reports that the explanation was a glacial collapse: A thick layer of ice had slid off the underlying rock, potentially because of warming at its bottommost layer, until it crashed into the valley below. There, the shattered ice and rock flowed down the Lhende Khola valley at speeds approaching 150 kilometers per hour, kicking off a flood that caused water levels to rise as much as 9 meters in 30 minutes.

KATHMANDU, Nepal (AP) — Residents along the Budhi Gandaki river in north central Nepal evacuated on Sunday as flash flooding destroyed homes and other structures in the area.

The National Disaster Risk Reduction and Management Authority evacuated villagers and warned others to move to safer areas while remaining on alert until late Sunday.

The agency said at least five people are reported missing so far. The flash flood also damaged or destroyed four bridges, swept away about three dozen houses and damaged the construction site of a hydropower plant.

Several power and communication towers were also damaged along the riverside.

The Budhi Gandaki river merges into the Trishuli river near Siurenitar (सिउरेनी टार), Ghyalchok, Gandaki Province, Nepal and Bahuntar (बाहुनटार ), Benighat, Bagmati Province. The floods extend along the Budhi Gandaki river from the Gorkha District, Gandaki Province, Nepal.