I don't think I've seen a snuff film of that scale before. I'm not good with even fictional horror. This may haunt my dreams. For most of the people there was just nothing they could do. But others would have had a chance if they had run perpendicular to the flow and climbed like their life depended on it. I'll try to remember that the next time I'm fleeing in panic from a flash flood.
Looks like a warning siren could have saved some lives. But apparently this was a black swan.
markdown · 2026-08-26 23:39:32 UTC
I think the Japan tsunami videos showed as many, but it was spread out over the course of almost 2hrs and happened in slow motion over a large area. You could see some cars speeding to safety while others were washed away. Some stayed in taller structures assuming they were safe and were slowly washed away.
ghastmaster · 2026-08-27 00:27:02 UTC
Perpendicular is not the scientifically best path. 45 degree angle is the best angle if the threat is moving toward you at the same velocity that you can move. As the velocity of the threat increases, the angle gets closer to perpendicular. The size of the threat and distance of course matter as well. I think about this before tree felling. In chainsaw classes they teach you to move at a 45.
Reason077 · 2026-08-27 00:55:24 UTC
Looking at the footage, the water/avalanche was moving far faster than anyone could move on foot. Well over 100 km/h, I would estimate.
dgellow · 2026-08-27 12:04:11 UTC
And taking the entire infrastructure with it, including buildings and roads
dredmorbius · 2026-08-28 01:05:16 UTC
Scrubbed bare from what I've seen to date of post-incident footage, though that's still preliminary.
dreamcompiler · 2026-08-27 01:51:09 UTC
Likewise if your car stalls on a railroad crossing, run at a 45 degree angle toward the train. This puts you away from the path of flying debris.
ANH · 2026-08-27 01:00:52 UTC
| But apparently this was a black swan.
What is your definition of black swan? This paper is from 2022 and scientists have been warning about climate change for decades. It's not like this possibility wasn't anticipated. It seems likely we'll see more glacial events as the atmosphere warms.
throwup238 · 2026-08-27 01:53:55 UTC
There have been maybe three such events in the 21st century (glacier or landslides producing more than a magnitude 5 quake), and none of them have happened in an area like the Himalayas. The other two were in Alaska on Mt Steller in 2005 and the Lamplugh Glacier in 2016, neither of which produced massive downstream floods.
It usually takes entire icebergs calving off to produce such seismic events and intense monsoons to create such flooding.
ElProlactin · 2026-08-27 02:29:12 UTC
> There have been maybe three such events in the 21st century
It seems that past history (especially recent) will not be a good predictor of future events.
throwup238 · 2026-08-27 02:43:27 UTC
Spoiler alert: that’s the whole point of a black swan event.
ElProlactin · 2026-08-27 03:25:38 UTC
A black swan event is an event that is unpredictable because it is so rare.
While I'd wait for confirmation about the cause of this specific incident, the point you seem to be ignoring is that, due to climate change, events that would have been considered "black swans" historically will become more and more common, to the point that they are expected to occur.
throwup238 · 2026-08-27 03:57:36 UTC
I think that’s a misreading of the entire book. A black swan event is a rare, high-impact outlier that is nearly impossible to predict under normal circumstances, but is rationalized as having been inevitable in hindsight.
ElProlactin · 2026-08-27 04:35:06 UTC
For whatever reason, you continue to try to ignore the point I'm making, which is that, in terms of natural disasters related to climate in particular, what would have been "rare, high-impact outlier[s]" are increasingly becoming common enough to be not rare and not outliers.
throwup238 · 2026-08-27 05:14:46 UTC
And you continue to ignore what I said (and what the book said). The whole point of a black swan event is exactly what you just described.
It’s the inflection point when our priors change.
fc417fc802 · 2026-08-27 06:31:48 UTC
Maybe I misunderstand (either you or the topic in general) but I don't think what you're saying is correct. A black swan event is (to my understanding) something unexpected and generally remains so. Not (as you seem to be suggesting) "oh hey that was historically unexpected but going forward it's now considered a standard contingency".
And I have no idea where you got the "rationalized as inevitable in hindsight" thing. I've never heard of that in relation to black swan events before.
gos9 · 2026-08-27 07:04:25 UTC
Have you read the book?
crote · 2026-08-27 08:47:12 UTC
If events like these are "nearly impossible to predict", how come this post is linking to a scientific paper predicting exactly this scenario?
This flood is like The Big One in California. We know it is going to happen, it is virtually a certainty. The only question is when and where.
If glacial floods come as a surprise to you, it is only because you have been deliberately ignoring all the climate change warnings. So, a short recap: we'll see massive droughts, giant wildfires, huge floods due to rainfall, significantly more intense hurricanes, mass starvation due to large-scale crop failure, and low-lying countries drowning due to sea level rise. Oh, and add a high likelihood of the AMOC collapsing triggering a cooldown of the East Coast and Europe to the list.
dredmorbius · 2026-08-27 05:19:14 UTC
Anticipation is one thing, effective response in the seconds before disaster strikes is quite another thing. This might not have been an absolute black swan, but even with foresight it is challenging in the extreme to avoid risk.
I've been reviewing what coverage I can find of the present event in Nepal/China, in context with Section 5.1, "Comprehensive approach to disaster risk management", of TFA.
It seems that what would be required would be:
- Active surveillance of glacial lake formation.
- Active mitigation of glacial lakes, reducing risk.
- Warning and response infrastructure, procedures, and protocols along the likly flood path.
From video of what I presume are among the worst-hit areas (see: <https://twitterwebviewer.com/?tweet=2092542957060841592>), there appear to have been at best a few seconds of warning. Very robust structures are demolished virtually instantly. Even had people been sheltering within those structures, or headed up-slope above the water flow, either structural integrity would prove insufficient, or response time inadequate to reach a safe elevation above the debris flow. The latter problem is compounded by what appears to be an extraordinarily strong air blast (likely hurricane-strength or greater) as well as massive amounts of airborne debris, much of it rock.
Terrain is severely constrained in the region, and the only buildable regions are in river valleys themselves. The Gyirong Port border crossing is located deep within a river channel, and despite robust construction simply could not survive the event.
(Take a few minutes to examine the region around the port itself ... there are several communities and businesses all well within the disaster zone, and I suspect that obliteration to those matches or exceeds what was captured on video at the crossing itself.)
From the first video at this Twitter post, a camera situated roughly 20m above the base terrain did not survive the event (though it transmitted for roughly a minute).
A second camera (I believe near the same location) shows similarly catastrophic damage, and no chance for anyone at base level to climb to a safe elevation before being overtaken by the debris flow.
Climbing that far would require 4--8 minutes for even a highly-fit person. Available response time in the videos I've seen is on the order of 1--2 minutes. Anyone beginning within the debris zone is already walking dead.
As the Cowboy Junkies said:
But if there's on thing in my life
That these years have taught
It's that you can always see it coming
But you can never stop it
Anticipation isn't sufficient. Other than entirely abandoning such locations during all periods of high risk, loss of life is likely, and catastrophic property and infrastructure damage inevitable.
When I was researching this morning I found papers related to this kind of risk from at least 2000. Given 20 years there could have been things done I think. And there is a lot of settlement on the tops of the ranges in that area too.. Maybe the roads have to be on the river valley, but not everything else. People living there could have been offered alternative land to move out of the path of it.. monitoring and early warning could have been set up.. at the checkpoint, if it had to be there, there could have been a big evacuation tunnel carved into the hillside, or something.. I guess Nepal doesn't have a lot of resources though.
The same thing even happened a year ago in the sample place, but at a smaller size
https://www.stimson.org/2025/investigating-an-emerging-clima...
lazide · 2026-08-27 07:20:36 UTC
Flat lowland is great because it's cheap and easy to build on, and not a hassle to actually use.
Ridgelines and slopes are terrible to build on (and often use) because there is little to no actual flat usable area without extensive construction. They also tend to be unstable and slide/erode.
That said, if I was in that area, of course i'd never build/live on anything but the highest ridgeline or slope around.
One of those 'long term/outlier risks cause daily costs' type of things. :s
dredmorbius · 2026-08-28 00:24:34 UTC
So, one of the most notably impacted locations to date has been the Gyirong port border crossing, noted in a couple of my earlier comments. Part of that is due to there being surveillance closed-circuit camera footage available, and there are other areas which would have been similarly affected. A few additional thoughts and facts have come to light:
- The crossing was substantially renovated in January of this year following an earlier flood which washed out the bridge connecting the station (in China) to Nepal.
- The crossing, part of China's Belt and Road Initiative (<https://en.wikipedia.org/wiki/Belt_and_Road_Initiative>), by needs must sit on the principal highway through the region. Which ... follows the river valley. Now, it's possible for that highway to be raised substantially off the valley floor, but consider that "inundations reached heights of 800m (2,600 ft) in a valley some 7km (4.3 mi) from the origin" (<https://www3.nhk.or.jp/nhkworld/en/news/20260827_22/>, via Wikipedia).
- The inundation reached the Gyirong port seven minutes after the initial avalanche. Even with absolutely timely warnings, that is only just barely enough time for a fit person to reach a safe elevation above the port itself. Wikipedia now mentions two people (of apparently hundreds present) being rescued from Gyirong port.
- Early reconnaissance footage above the site of the former Gyirong port shows nothing but bare land. All of the apparently quite substantial structures on the site were simply scrubbed from existence. The forces involved are formidable. <https://www.globaltimes.cn/page/202608/1369215.shtml>
- The event is, as has been noted, foreseable, but also unprecedented. There are no events of comparable magnitude in the area, despite previous flooding. The likelihood that this week's incident represents a potential new baseline must be considered.
- Debris flows were moving at roughly 50m/s, or 180 kph (about 110 mph). That's not only an absolutely formidable speed, but a formidable force, where kinetic energy = mass * velocity squared.
The only possible safe refuge I could see would be some sort of underground bunker, into which all staff and travelers would have to locate to in a matter of seconds, and then sealed against water intake, this in a busy border crossing with multiple nationalities and languages in a region with a < 70% literacy rate.
And that's for the Gyirong border station itself. Note that that was a Chinese facility, where China is the vastly wealthier and better-resourced partner to Nepal. Nepal's capabilities to effect similar measures at an equivalent facility or in numerous communities throughout the region is quite limited.
Also affected were numerous other facilities, including a shrine (being visited by numerous Hindu pilgrims), apparently utterly destroyed and all present killed, numerous villages, etc. Roads are heavily damaged if present at all, bridges are washed away, and in a region with tens to hundreds of thousands of inhabitants (based on various county/district Wikipedia pages I've examined), a dozen or so rescue helicopters have so far been summoned.
Black swans are actually fairly well-populated birds that are easy to spot. So as a metaphor it works well for a common thing that smug people of limited knowledge try to claim is rare and surprising.
suzzer99 · 2026-08-27 01:04:59 UTC
I wonder if the river went dry first, like the water receding off into the horizon before a tsunami?
ghastmaster · 2026-08-27 01:11:20 UTC
It is possible if you consider madaxe_again's theory(comment here). If the debris just started descending without interruption, there would be no receding.
suzzer99 · 2026-08-27 02:36:45 UTC
Well supposedly it was caused by a landslide blocking the river for a few minutes, then the dam burst all at once.
dredmorbius · 2026-08-28 00:51:49 UTC
Based on video footage which has emerged, no.
colechristensen · 2026-08-27 01:20:26 UTC
The great flood myths across the world are quite possibly ancestral memories of this kind of flood on a continental scale. Retreating ice age glaciers would make lakes the size of states held at bay by an impromptu dam of various kinds of debris (or more glacier) which then would break dumping great lake amounts of water hundreds of miles into the ocean within days. This kind of thing probably happened in lots of places.
delichon · 2026-08-27 02:30:25 UTC
You just pushed me into a rabbit hole called the Zanclean megaflood.
It is supposed that such an event happened, when the land between continental Europe and England got flooded. This was as well during a warmer period when glacier melted. And there was human population on that land.
Oh there's geological evidence of these things happening in the pacific northwest, the waves and water scouring the landscape in an unimaginable fashion left evidence to be seen today. Like 1000 Niagra falls for a month straight. Outflows measured in billions of gallons per second or 10+ cubic kilometers per hour.
Yes this is exactly the kind of thing i'm talking about and in the time frame which is at least plausible to make its way through mythology to modern day (not so much for the flooding of a dry mediterranean sea five million years ago)
dredmorbius · 2026-08-28 00:51:24 UTC
The flooding of the Black Sea, OTOH, might have played a part in the Flood Myth, having occurred around 7,600 years ago (5600 BCE):
There was another similar flood on the same river about a year or two ago. The problem was the the glacial flooding started in Tibet and affected people just over the border (one of the videos is from the border crossing). There's no international data sharing for this sort of thing between China and Nepal and Nepal can't deploy sensors in Tibet to give sufficient warning.
21asdffdsa12 · 2026-08-27 06:24:06 UTC
We have tsunami warnings all the times now. Nobody is stopping people from burying sensor posts upstream.
regularfry · 2026-08-27 10:56:03 UTC
I suspect you are dramatically overestimating how fast humans can climb. I hope I'm wrong.
dredmorbius · 2026-08-28 01:04:43 UTC
From further information that's emerged:
- The site captured in the video, the Gyirong Port border crossing between China and Nepal, was struck by the flood roughly seven minutes after the presumed avalanche thought to have triggered the event.
- Flood inundation is seen up to 800 m (2,600 ft) above river level, and the camera position in the video at approximately 20--25m (roughly 6--8 stories) above ground level was engaged in the debris flow.
- It would take a fit person 4--8 minutes to climb even 250m or so above ground level, presuming instant notification and a clear evacuation path. Even with an instant warning of upstream conditions survival was overwhelmingly unlikely.
- Subsequent footage appears to show complete obliteration off all structures, with no trace remaining. This is based on preliminary imagery, without precise location information, and in a landscape changed beyond all recognition.
- Astoundingly, two survivors from the Port are mentioned in Wikipedia presently.
Though yes, one of the peculiarities of flood risk is that elevation equals safety. That's modulo a number of other factors though.
In particular, with an event of this magnitude, wind blast is a major effect. Toward the end of one video a line of buses in a car park is seen shifting backward, I suspect due to wind. These can reach well above hurricane force, and of course carries its own debris and threats, where even grass and straw can penetrate deeply. There's also the risk of secondary landslides and the like in steep terrain. One of the regions affected by this event has an etymology from "mud wall", which may be a reference to the geology of the canyon walls themselves. Those could easily be unstable.
Best option is to be lucky and not be there when things go horribly wrong.
arjie · 2026-08-26 23:20:05 UTC
150 confirmed with 47 Americans? Surprising fraction. Mountaineers or that area is popular for some reason?
markus_zhang · 2026-08-26 23:20:46 UTC
Nepal is popular for Westerners I think. Maybe for religious reasons?
porridgeraisin · 2026-08-27 05:56:59 UTC
Mountaineering.
For indians, you also have the religious aspect because the immigration center you go to to visit Mt Kailash is there.
That immigration building was the white one that got completely shredded in the popular video going around.
markus_zhang · 2026-08-27 10:11:02 UTC
Ah thanks for clarification.
janhaa · 2026-08-26 23:28:55 UTC
i understand it as 150 dead, with more people missing, of which 47 are americans.
segmondy · 2026-08-26 23:38:56 UTC
Way too early to get an accurate count
suzzer99 · 2026-08-27 01:05:38 UTC
I feel like I've easily seen more than that get swept away in videos.
lazide · 2026-08-27 08:08:57 UTC
Zero chance the actual death count is sub-1000
adelie · 2026-08-26 23:39:27 UTC
it's a popular area for tourists and mountaineers, but also i think it's a lot easier to estimate missing/dead tourists since most of them will be there with tours/companies that have to keep track of exactly where they are.
keyle · 2026-08-27 00:16:12 UTC
Likely the tourists are better accounted for than the locals. Numbers are likely much higher :(
don_esteban · 2026-08-27 07:20:21 UTC
This.
You could probably count 100+ people in the death zone of the border crossing video alone. The final death toll will be terrible, with most never found.
tppiotrowski · 2026-08-27 01:38:17 UTC
Syabru Besi is downriver of the border and the starting point for the Langtang valley trek which is probably the third most popular trekking location in Nepal (behind Everest basecamp and Annapurna circuit). I think the tourist data they have is from tourists that are traveling with guides but from my experience many tourists also bypass the official requirements and trek solo so the number could be much higher if the Langtang is affected.
markus_zhang · 2026-08-26 23:20:20 UTC
I have watched a few and they look like the four horsemen TBH.
alephnerd · 2026-08-27 02:40:21 UTC
It is harrowing. It also explains why the villages in my ancestral region in India (JK, HP, UK) with close cultural and ethnic ties with Nepal used to build them at the upper portions of the sides of mountains/hills and only shifted to building at the bottom of those kinds of valleys when motorized roads became a thing in the 20th century.
Rescue operations in Nepal are in good hands, but this is sadly because those same response orgs had to respond to a similarly brutal cloud burst floods back in 2013 [0], 2021 [1] and 2025 [2].
It also shows the very real and brutal effect climate change is already having, and will only get worse.
The debris flow that has just happened doesn’t appear to be a glacial outburst.
Rather, the entire front face of a glacier at high elevation sheared off, likely millions of tonnes of material at least, crashed down a steep runnel, slammed into the opposing slope on the other side of the valley at the bottom, made that partially collapse, dammed the river for several minutes, and then all descended at high speed as the dam failed, with the results we see.
Some reportage is still saying there was an earthquake - there wasn’t - the landslide itself was the source of the seismic waves.
Brilliant analysis! Although china is notoriously bad at reporting earthquake data, I assumed in this case they were open and honest. It made sense that an earthquake would trigger this event. I do not fault anyone for interpreting the data this way. The USGS has been the agency I most trust in the federal government.
USGS is a fact finding organization. They do not regulate. They have been around since 1879. The land surveys they have done made huge impact on society. The reliability of surveys that they have facilitated has made an impact on industrial civilization that few will understand or ever hear about.
inasio · 2026-08-26 23:08:01 UTC
Reminded me of the Huascaran avalanche (1970, killed approx 30K people) [0]. I'm surprised this is not also in the thousands of casualties (perhaps it'll get there) [0]
I believe this is how the Hudson Bay was formed, in what must have been quite a sight.
metalman · 2026-08-27 00:34:51 UTC
GLOF, glacial lake outburst flood.
exceptionaly brutal cctv footage from the tibet/nepal border, so many people that there is a tiny chance that perhaps one of them was tossed clear, but of the rest there will be no remains.
other videos shows that the flood "water" is so thick with mud that it is sheering off in sheets and one more shows it ripping out a concrete bridge that then floats away on top.
*disturbing video
Otherwise China report 3 dead and 558 missing, not clear if at the port itself or the surrounding county, or how accurate counts of those present at the port might be.
mandeepj · 2026-08-27 02:50:40 UTC
In the future, don't go close to mountains during monsoon season - late May to August end; that period is specifically for Southeast Asia. For the rest of the world, you can find it out.
bamboozled · 2026-08-27 03:07:36 UTC
I read this wasn't due to rain but a glacial collapse. It sounds to me like the additional advice would be that due to a warming climate, avoid being under a glacier at all costs?
defrost · 2026-08-27 03:18:10 UTC
Down stream of a glacier, in the run off water shed.
As I've heard tell, this was a glacial collapse into and blocking a river, which then built up a head of pressure behind it, bursting to release a hammer blow of river water and debris that travelled a great distance.
Similar things can happen due to landslides into rivers; it depends on the topology of the land, here long narrow valleys carved out by heavy water flows.
The warning being, don't live in a natural "drainpipe".
In mountainous regions that's often not much of an option, there's a lot of vertical sides and valley bottoms.
bamboozled · 2026-08-27 04:10:58 UTC
It sounds like there may have been some opportunity for warning then? If the thing was more of a "build up" ?
defrost · 2026-08-27 04:17:30 UTC
Sure, if every part of rugged terrain were monitored with sufficient frequency to detect such a change.
That might take some infrastructure to cover everywhere such things can happen (eg: the beds of rivers in Western Australia's Pilbara and Kimberley regions have a high flash flooding risk in the wet season.
bamboozled · 2026-08-27 12:12:59 UTC
Sounds like a great application for drone tech.
defrost · 2026-08-27 12:17:56 UTC
Is it?
What's the land area you'd like seamlessly and continuously monitored by a mobile object with moving parts ... and how is that a better solution than using static solar powered instrumentation?
mandeepj · 2026-08-28 01:13:08 UTC
Better suited for satellites
dredmorbius · 2026-08-28 02:00:14 UTC
Satellites or ground-based observation.
Geologists have used the latter for many decades. Monitors upslope of at-risk glaciers, solar/battery powered, and communicating by radio (or Internet / satellite links) could be part of this.
See for example the extensive seismic monitoring of California's San Andreas Fault, particularly at Parkfield and through the Carrizo Plain / CA Hwy 25.
(Different tech, obviously, but in situ ground-based sensors which share some similarities.)
defrost · 2026-08-28 02:38:12 UTC
Ground based field instrumentation on specific potential threats has the advantages of being up close and always on target whereas sat observation is distant and intermittent.
Multiple sat observations a day is great, obviously, but sudden collapses / changes often won't get flagged for seven or eight hours after the event.
jltsiren · 2026-08-27 05:32:04 UTC
The rivers in that area are pretty small. You would have to block them for days before there is a risk of a massive flash flood.
From what I've understood, the collapsing glacier either contained enough liquid water or melted enough from the impact that it continued flowing downstream. It covered ~20 horizontal kilometers in about 7 minutes before hitting the border crossing.
defrost · 2026-08-27 07:31:11 UTC
There's a few ways this could go and very likely no video feed to be sure.
It had the look of a large volume of water quickly released.
Massive tonnages breaking off of a glacier is still going to be mostly ice on impact .. there's a chance debris and ice chunks made a temporary dam as the bulk of the now shattered glacier ice released water putting pressure on that weak dam - leading to collapse and release.
dredmorbius · 2026-08-28 01:54:56 UTC
The specific geological cause is not yet clear.
We do know that a glacier substantially collapsed.
What contributed to the amount of water in the debris flow isn't clear. Speculation, from trained geologists, is that the friction of the glacier flow itself contributed to melt. I'm speculating that recent rains or higher temperatures might have contributed to melting on the glacier (and have seen some commentary speculating about this).
Speculating on my part: There might also have been accumulated water below the glacier, liberated by the ice flow, or perhaps groundwater which was evacuated along with other material. Events seem to have precipitated too quickly (roughly 7 minutes from galcial collapse to Gyirong Port inundation) for the collapse to have formed, then broken, a dam on tributary waterways upstream of the port.
GLOF is a recognised threat, but this event seems to have been at best only partially explained by that, and may be an entirely different mechanism. The follow-on studies should be fascinating, in the way that horrific disasters often are.
defrost · 2026-08-28 02:33:02 UTC
That all tracks - good additional comment.
> Speculation, from trained geologists
Probably about on par with speculation from trained geophysicists I'd warrant.
dredmorbius · 2026-08-28 14:53:54 UTC
Thanks.
Re "speculation, ...": my point being expertise, but based on background knowledge rather than close event-specific observations or measurements. Yes, geophysicists would be an equivalent level of expertise.
>simulated worst-case outburst events from these lakes both in the Tibetan town of Nyalam and downstream at the border with Nepal
For context that's not where the flood happened, there's a massive mountain range in between those vallies reaching over 8000m (Shishapangma).
In earth science there are thousands of worst case scenario models published, but it's hard to actually predict reality.
21asdffdsa12 · 2026-08-27 06:22:58 UTC
Its easy though to bury sensors and sound sirens.
lazide · 2026-08-27 08:04:13 UTC
Not in all potential areas across such rough terrain.
21asdffdsa12 · 2026-08-27 08:41:42 UTC
Its a "detect characteristic vibrations" - send to starlink? or if thats the problem- use the river itself and transmit the warning with the speed of sound through water.. by just having some underwater bell upstream. Go full lowtech, but at the risk of no warning if the river is dry at glacier dam break.
trompetenaccoun · 2026-08-27 11:23:39 UTC
There are definitely countries that have very good warning systems. Japan comes to mind. As for Nepal I wouldn't expect it though, and even in China devastating flood events happen regularly in more populated areas than the Himalayas, where people could have been saved if they'd been warned. Despite China's excellent mobile coverage, that doesn't seem to be the issue.
yccs27 · 2026-08-27 12:34:33 UTC
It's just the opposite side of the same mountain, used as a case study for modeling GLOF risk. In fact, they prominently cite "Potentially dangerous glacial lakes across the Tibetan Plateau" [1], which includes Gyirong Port and the downstream valley as a high risk of GLOFs and notes that many buildings there are exposed to potential flash flooding. Take a look at Fig. 5 [2] - the upper left cluster of dangerous lakes and exposed buildings is the site of the disaster. They also name Jilong, Nyalam, Dingri and Kangding as the Tibetan counties with the highest lake danger; the glacier collapse happened at the border of Jilong county.
Clearly the point of this paper was not to flag a specific lake as being a specific problem. It seems pretty clear it's a case study meant to provide generalizable information and principals for remediation, and while they didn't predict the exact glacial lake that would collapse first, they were flagging danger in exactly the right region.
Comments
Looks like a warning siren could have saved some lives. But apparently this was a black swan.
What is your definition of black swan? This paper is from 2022 and scientists have been warning about climate change for decades. It's not like this possibility wasn't anticipated. It seems likely we'll see more glacial events as the atmosphere warms.
It usually takes entire icebergs calving off to produce such seismic events and intense monsoons to create such flooding.
It seems that past history (especially recent) will not be a good predictor of future events.
While I'd wait for confirmation about the cause of this specific incident, the point you seem to be ignoring is that, due to climate change, events that would have been considered "black swans" historically will become more and more common, to the point that they are expected to occur.
It’s the inflection point when our priors change.
And I have no idea where you got the "rationalized as inevitable in hindsight" thing. I've never heard of that in relation to black swan events before.
This flood is like The Big One in California. We know it is going to happen, it is virtually a certainty. The only question is when and where.
If glacial floods come as a surprise to you, it is only because you have been deliberately ignoring all the climate change warnings. So, a short recap: we'll see massive droughts, giant wildfires, huge floods due to rainfall, significantly more intense hurricanes, mass starvation due to large-scale crop failure, and low-lying countries drowning due to sea level rise. Oh, and add a high likelihood of the AMOC collapsing triggering a cooldown of the East Coast and Europe to the list.
I've been reviewing what coverage I can find of the present event in Nepal/China, in context with Section 5.1, "Comprehensive approach to disaster risk management", of TFA.
It seems that what would be required would be:
- Active surveillance of glacial lake formation.
- Active mitigation of glacial lakes, reducing risk.
- Warning and response infrastructure, procedures, and protocols along the likly flood path.
From video of what I presume are among the worst-hit areas (see: <https://twitterwebviewer.com/?tweet=2092542957060841592>), there appear to have been at best a few seconds of warning. Very robust structures are demolished virtually instantly. Even had people been sheltering within those structures, or headed up-slope above the water flow, either structural integrity would prove insufficient, or response time inadequate to reach a safe elevation above the debris flow. The latter problem is compounded by what appears to be an extraordinarily strong air blast (likely hurricane-strength or greater) as well as massive amounts of airborne debris, much of it rock.
Terrain is severely constrained in the region, and the only buildable regions are in river valleys themselves. The Gyirong Port border crossing is located deep within a river channel, and despite robust construction simply could not survive the event.
See:
<https://en.wikipedia.org/wiki/Gyirong_Port> (Wikipedia article on the port.)
Map / satellite view: <https://www.google.com/maps/@28.2792579,85.3752907,1341m/dat...>
(Take a few minutes to examine the region around the port itself ... there are several communities and businesses all well within the disaster zone, and I suspect that obliteration to those matches or exceeds what was captured on video at the crossing itself.)
From the first video at this Twitter post, a camera situated roughly 20m above the base terrain did not survive the event (though it transmitted for roughly a minute).
A second camera (I believe near the same location) shows similarly catastrophic damage, and no chance for anyone at base level to climb to a safe elevation before being overtaken by the debris flow.
Wikipedia notes "Floodwaters reached settlements as high as 270 feet (80 m) above the river level", citing <https://english.onlinekhabar.com/rasuwa-flood-in-pictures.ht...>.
Climbing that far would require 4--8 minutes for even a highly-fit person. Available response time in the videos I've seen is on the order of 1--2 minutes. Anyone beginning within the debris zone is already walking dead.
As the Cowboy Junkies said:
Anticipation isn't sufficient. Other than entirely abandoning such locations during all periods of high risk, loss of life is likely, and catastrophic property and infrastructure damage inevitable.<https://twitterwebviewer.com/?tweet=2092542957060841592>
Ridgelines and slopes are terrible to build on (and often use) because there is little to no actual flat usable area without extensive construction. They also tend to be unstable and slide/erode.
That said, if I was in that area, of course i'd never build/live on anything but the highest ridgeline or slope around.
One of those 'long term/outlier risks cause daily costs' type of things. :s
- The crossing was substantially renovated in January of this year following an earlier flood which washed out the bridge connecting the station (in China) to Nepal.
- The crossing, part of China's Belt and Road Initiative (<https://en.wikipedia.org/wiki/Belt_and_Road_Initiative>), by needs must sit on the principal highway through the region. Which ... follows the river valley. Now, it's possible for that highway to be raised substantially off the valley floor, but consider that "inundations reached heights of 800m (2,600 ft) in a valley some 7km (4.3 mi) from the origin" (<https://www3.nhk.or.jp/nhkworld/en/news/20260827_22/>, via Wikipedia).
- The inundation reached the Gyirong port seven minutes after the initial avalanche. Even with absolutely timely warnings, that is only just barely enough time for a fit person to reach a safe elevation above the port itself. Wikipedia now mentions two people (of apparently hundreds present) being rescued from Gyirong port.
- Early reconnaissance footage above the site of the former Gyirong port shows nothing but bare land. All of the apparently quite substantial structures on the site were simply scrubbed from existence. The forces involved are formidable. <https://www.globaltimes.cn/page/202608/1369215.shtml>
I believe that the end of this video shows post-incident video of the same site, though frankly it's unrecognisable. I'm sure we'll have more definitive evidence soon. <https://www.msn.com/en-ca/video/other/china-video-shows-muds...>.
- The event is, as has been noted, foreseable, but also unprecedented. There are no events of comparable magnitude in the area, despite previous flooding. The likelihood that this week's incident represents a potential new baseline must be considered.
- Debris flows were moving at roughly 50m/s, or 180 kph (about 110 mph). That's not only an absolutely formidable speed, but a formidable force, where kinetic energy = mass * velocity squared.
The only possible safe refuge I could see would be some sort of underground bunker, into which all staff and travelers would have to locate to in a matter of seconds, and then sealed against water intake, this in a busy border crossing with multiple nationalities and languages in a region with a < 70% literacy rate.
And that's for the Gyirong border station itself. Note that that was a Chinese facility, where China is the vastly wealthier and better-resourced partner to Nepal. Nepal's capabilities to effect similar measures at an equivalent facility or in numerous communities throughout the region is quite limited.
Also affected were numerous other facilities, including a shrine (being visited by numerous Hindu pilgrims), apparently utterly destroyed and all present killed, numerous villages, etc. Roads are heavily damaged if present at all, bridges are washed away, and in a region with tens to hundreds of thousands of inhabitants (based on various county/district Wikipedia pages I've examined), a dozen or so rescue helicopters have so far been summoned.
Oh, and a new glacial/debris dam and lake have formed which is feared may pose an additional outburst flood event within days (<https://www.theguardian.com/world/2026/aug/27/nepal-tibet-fl...>).
https://en.wikipedia.org/wiki/Zanclean_flood
https://en.wikipedia.org/wiki/Doggerland
https://en.wikipedia.org/wiki/Channeled_Scablands
https://en.wikipedia.org/wiki/Missoula_floods
<https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis>
<https://en.wikipedia.org/wiki/Lake_Agassiz>
<https://www.nature.com/articles/nature08954>
<https://www.sciencedirect.com/science/article/abs/pii/S00335...>
<https://en.wikipedia.org/wiki/Younger_Dryas>
- The site captured in the video, the Gyirong Port border crossing between China and Nepal, was struck by the flood roughly seven minutes after the presumed avalanche thought to have triggered the event.
- Flood inundation is seen up to 800 m (2,600 ft) above river level, and the camera position in the video at approximately 20--25m (roughly 6--8 stories) above ground level was engaged in the debris flow.
- It would take a fit person 4--8 minutes to climb even 250m or so above ground level, presuming instant notification and a clear evacuation path. Even with an instant warning of upstream conditions survival was overwhelmingly unlikely.
- Subsequent footage appears to show complete obliteration off all structures, with no trace remaining. This is based on preliminary imagery, without precise location information, and in a landscape changed beyond all recognition.
- Astoundingly, two survivors from the Port are mentioned in Wikipedia presently.
Though yes, one of the peculiarities of flood risk is that elevation equals safety. That's modulo a number of other factors though.
In particular, with an event of this magnitude, wind blast is a major effect. Toward the end of one video a line of buses in a car park is seen shifting backward, I suspect due to wind. These can reach well above hurricane force, and of course carries its own debris and threats, where even grass and straw can penetrate deeply. There's also the risk of secondary landslides and the like in steep terrain. One of the regions affected by this event has an etymology from "mud wall", which may be a reference to the geology of the canyon walls themselves. Those could easily be unstable.
Best option is to be lucky and not be there when things go horribly wrong.
For indians, you also have the religious aspect because the immigration center you go to to visit Mt Kailash is there.
That immigration building was the white one that got completely shredded in the popular video going around.
You could probably count 100+ people in the death zone of the border crossing video alone. The final death toll will be terrible, with most never found.
Rescue operations in Nepal are in good hands, but this is sadly because those same response orgs had to respond to a similarly brutal cloud burst floods back in 2013 [0], 2021 [1] and 2025 [2].
It also shows the very real and brutal effect climate change is already having, and will only get worse.
[0] - https://en.wikipedia.org/wiki/2013_North_India_floods
[1] - https://en.wikipedia.org/wiki/2021_Uttarakhand_flood
[2] - https://en.wikipedia.org/wiki/2025_Kishtwar_district_flash_f...
That’s just pure horror, nightmare material
Rather, the entire front face of a glacier at high elevation sheared off, likely millions of tonnes of material at least, crashed down a steep runnel, slammed into the opposing slope on the other side of the valley at the bottom, made that partially collapse, dammed the river for several minutes, and then all descended at high speed as the dam failed, with the results we see.
Some reportage is still saying there was an earthquake - there wasn’t - the landslide itself was the source of the seismic waves.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000tbwb...
USGS is a fact finding organization. They do not regulate. They have been around since 1879. The land surveys they have done made huge impact on society. The reliability of surveys that they have facilitated has made an impact on industrial civilization that few will understand or ever hear about.
https://en.wikipedia.org/wiki/1970_Huascar%C3%A1n_debris_ava...
Similar death toll. Also Orion.
https://www.dogmanray.com/true-stories/orion/
exceptionaly brutal cctv footage from the tibet/nepal border, so many people that there is a tiny chance that perhaps one of them was tossed clear, but of the rest there will be no remains. other videos shows that the flood "water" is so thick with mud that it is sheering off in sheets and one more shows it ripping out a concrete bridge that then floats away on top. *disturbing video
https://m.youtube.com/watch?v=rIVNeDuCF_k
fixed, but some things are better off wrong perhaps
Not sure this is confirmed at this time.
<https://english.news.cn/20260827/a8eb0a7aedb34d9181793f5fbc0...>
Otherwise China report 3 dead and 558 missing, not clear if at the port itself or the surrounding county, or how accurate counts of those present at the port might be.
As I've heard tell, this was a glacial collapse into and blocking a river, which then built up a head of pressure behind it, bursting to release a hammer blow of river water and debris that travelled a great distance.
Similar things can happen due to landslides into rivers; it depends on the topology of the land, here long narrow valleys carved out by heavy water flows.
The warning being, don't live in a natural "drainpipe".
In mountainous regions that's often not much of an option, there's a lot of vertical sides and valley bottoms.
That might take some infrastructure to cover everywhere such things can happen (eg: the beds of rivers in Western Australia's Pilbara and Kimberley regions have a high flash flooding risk in the wet season.
What's the land area you'd like seamlessly and continuously monitored by a mobile object with moving parts ... and how is that a better solution than using static solar powered instrumentation?
Geologists have used the latter for many decades. Monitors upslope of at-risk glaciers, solar/battery powered, and communicating by radio (or Internet / satellite links) could be part of this.
See for example the extensive seismic monitoring of California's San Andreas Fault, particularly at Parkfield and through the Carrizo Plain / CA Hwy 25.
<https://earthquake.usgs.gov/learn/parkfield/safod_pbo.php>
<https://en.wikipedia.org/wiki/Carrizo_Plain>
<https://en.wikipedia.org/wiki/California_State_Route_25>
(Different tech, obviously, but in situ ground-based sensors which share some similarities.)
Multiple sat observations a day is great, obviously, but sudden collapses / changes often won't get flagged for seven or eight hours after the event.
From what I've understood, the collapsing glacier either contained enough liquid water or melted enough from the impact that it continued flowing downstream. It covered ~20 horizontal kilometers in about 7 minutes before hitting the border crossing.
It had the look of a large volume of water quickly released.
Massive tonnages breaking off of a glacier is still going to be mostly ice on impact .. there's a chance debris and ice chunks made a temporary dam as the bulk of the now shattered glacier ice released water putting pressure on that weak dam - leading to collapse and release.
We do know that a glacier substantially collapsed.
What contributed to the amount of water in the debris flow isn't clear. Speculation, from trained geologists, is that the friction of the glacier flow itself contributed to melt. I'm speculating that recent rains or higher temperatures might have contributed to melting on the glacier (and have seen some commentary speculating about this).
Speculating on my part: There might also have been accumulated water below the glacier, liberated by the ice flow, or perhaps groundwater which was evacuated along with other material. Events seem to have precipitated too quickly (roughly 7 minutes from galcial collapse to Gyirong Port inundation) for the collapse to have formed, then broken, a dam on tributary waterways upstream of the port.
GLOF is a recognised threat, but this event seems to have been at best only partially explained by that, and may be an entirely different mechanism. The follow-on studies should be fascinating, in the way that horrific disasters often are.
> Speculation, from trained geologists
Probably about on par with speculation from trained geophysicists I'd warrant.
Re "speculation, ...": my point being expertise, but based on background knowledge rather than close event-specific observations or measurements. Yes, geophysicists would be an equivalent level of expertise.
For context that's not where the flood happened, there's a massive mountain range in between those vallies reaching over 8000m (Shishapangma).
In earth science there are thousands of worst case scenario models published, but it's hard to actually predict reality.
[1] referenced as Allen et al. (2019), https://doi.org/10.1016/j.scib.2019.03.011
[2] https://ars.els-cdn.com/content/image/1-s2.0-S20959273193015...