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Worst-case glacial lake flood scenarios in a transboundary Himalayan basin 2022
- ChiperSoft 21d agoContext: https://www.cnn.com/2026/08/26/world/live-news/nepal-flash-flooding-floods-intl https://www.cnn.com/2026/08/26/world/live-news/nepal-flash-f...
- delichon 21d agoI 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 21d agoI 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 21d agoPerpendicular 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 21d agoLooking 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 21d agoAnd taking the entire infrastructure with it, including buildings and roads
- dredmorbius 20d agoScrubbed bare from what I've seen to date of post-incident footage, though that's still preliminary.
- dreamcompiler 21d agoLikewise 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 21d ago| 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 21d agoThere 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 21d ago> 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 21d agoSpoiler alert: that’s the whole point of a black swan event.
- ElProlactin 21d agoA 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 21d ago
- suzzer99 21d agoI wonder if the river went dry first, like the water receding off into the horizon before a tsunami?
- ghastmaster 21d agoIt 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 21d agoWell supposedly it was caused by a landslide blocking the river for a few minutes, then the dam burst all at once.
- dredmorbius 20d agoBased on video footage which has emerged, no.
- colechristensen 21d agoThe 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 21d agoYou just pushed me into a rabbit hole called the Zanclean megaflood. https://en.wikipedia.org/wiki/Zanclean_flood https://en.wikipedia.org/wiki/Zanclean_flood
- hommelix 21d agoIt 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. https://en.wikipedia.org/wiki/Doggerland https://en.wikipedia.org/wiki/Doggerland
- colechristensen 21d agoOh 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. https://en.wikipedia.org/wiki/Channeled_Scablands https://en.wikipedia.org/wiki/Channeled_Scablands
- GolfPopper 21d agoThe Missoula Floods in the northwestern US were a similar sort of event, though I'm not sure how the scale compares. https://en.wikipedia.org/wiki/Missoula_floods https://en.wikipedia.org/wiki/Missoula_floods
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- scheme271 21d agoThere 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 21d agoWe have tsunami warnings all the times now. Nobody is stopping people from burying sensor posts upstream.
- regularfry 21d agoI suspect you are dramatically overestimating how fast humans can climb. I hope I'm wrong.
- dredmorbius 20d agoFrom 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 21d ago150 confirmed with 47 Americans? Surprising fraction. Mountaineers or that area is popular for some reason?
- markus_zhang 21d agoNepal is popular for Westerners I think. Maybe for religious reasons?
- porridgeraisin 21d agoMountaineering. 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 21d agoAh thanks for clarification.
- janhaa 21d agoi understand it as 150 dead, with more people missing, of which 47 are americans.
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- markus_zhang 21d agoI have watched a few and they look like the four horsemen TBH.
- alephnerd 21d agoIt 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. [0] - https://en.wikipedia.org/wiki/2013_North_India_floods https://en.wikipedia.org/wiki/2013_North_India_floods [1] - https://en.wikipedia.org/wiki/2021_Uttarakhand_flood https://en.wikipedia.org/wiki/2021_Uttarakhand_flood [2] - https://en.wikipedia.org/wiki/2025_Kishtwar_district_flash_flood https://en.wikipedia.org/wiki/2025_Kishtwar_district_flash_f...
- totetsu 21d agoThat makes sense. You can see lots of settlements on the hills above the sight of this flood too. I also found this study of the risk perceptions of people living there interesting too. https://www.sciencedirect.com/science/article/pii/S2212420924002383 https://www.sciencedirect.com/science/article/pii/S221242092...
- dgellow 21d agoLook at the CCTV at https://apnews.com/article/climate-change-nepal-tibet-glacier-collapse-floods-61b592d428e4631add31ce052d0daf1f https://apnews.com/article/climate-change-nepal-tibet-glacie... (second video in the carousel). That’s just pure horror, nightmare material
- madaxe_again 21d agoThe 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. https://earthquake.usgs.gov/earthquakes/eventpage/us7000tbwb/executive https://earthquake.usgs.gov/earthquakes/eventpage/us7000tbwb...
- ghastmaster 21d agoBrilliant 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 21d agoReminded 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] https://en.wikipedia.org/wiki/1970_Huascar%C3%A1n_debris_avalanche https://en.wikipedia.org/wiki/1970_Huascar%C3%A1n_debris_ava...
- jvanderbot 21d agoI believe this is how the Hudson Bay was formed, in what must have been quite a sight.
- ghastmaster 21d ago[flagged]
- metalman 21d agoGLOF, 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 https://m.youtube.com/watch?v=rIVNeDuCF_k https://m.youtube.com/watch?v=rIVNeDuCF_k
- chinathrow 21d ago> GLOF, glacial lake outburst flood. Not sure this is confirmed at this time.
- bamboozled 21d agoWrong link
- metalman 21d agohttps://m.youtube.com/watch?v=rIVNeDuCF_k https://m.youtube.com/watch?v=rIVNeDuCF_k fixed, but some things are better off wrong perhaps
- dredmorbius 20d agoTwo local villagers have been rescued from the Gyirong Port region, though it's not clear if they were at the port itself: <https://english.news.cn/20260827/a8eb0a7aedb34d9181793f5fbc01397a/c.html 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.
- mandeepj 21d agoIn 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 21d agoI 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 21d agoDown 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 21d agoIt sounds like there may have been some opportunity for warning then? If the thing was more of a "build up" ?
- defrost 21d agoSure, 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.
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- trompetenaccoun 21d ago>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 21d agoIts easy though to bury sensors and sound sirens.
- lazide 21d agoNot in all potential areas across such rough terrain.
- 21asdffdsa12 21d agoIts 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 21d agoThere 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 21d agoIt'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. [1] referenced as Allen et al. (2019), https://doi.org/10.1016/j.scib.2019.03.011 https://doi.org/10.1016/j.scib.2019.03.011 [2] https://ars.els-cdn.com/content/image/1-s2.0-S2095927319301501-gr5.jpg https://ars.els-cdn.com/content/image/1-s2.0-S20959273193015...
- vmh1928 21d agoNear Juneau, Alaska, USA, the Mendenhall glacier has repeatedly, over the last few years, had a Glacial Lake Outburst Flood. Not nearly as catastrophic as the one in Nepal but it did flood areas near Mendenhall River in Juneau. The latest event was August 13, 2026. https://www.weather.gov/ajk/suicidebasin https://www.weather.gov/ajk/suicidebasin
- yolo3000 21d agoReminded me of this documentary I saw last year - https://www.arte.tv/en/videos/122807-000-A/arte-reportage/ https://www.arte.tv/en/videos/122807-000-A/arte-reportage/ . I thought it was the same lake
- brainless 21d agoI can understand that this is not the exact location where the floods actually happened. But I am sad and I am frustrated and I am angry. We had floods in Sikkim, which is practically a "stone throw" away from a world-level map point of view. I was there then. There was past research but everyone was so surprised. Activists talking about that event 10 years prior. Published reports. Yet, we do nothing to move people away. To pause and think what the hell is going wrong. Just keep hustling and pretend shit is not going to go wrong. I am tired of our* culture. our: all of us, I am not only talking about India, Nepal or China here.
- shrubby 21d agoYes. Aleksey Yurchak coined a term Hupernormalisation and it works here too. We know the reality, yet leaders keep telling us via TV, social media... that everything is fine. We know that they know that we know. Fake world? Matrix? Escape from the freedom?
- O-K 21d agoThere’s a great doc by Adam Curtis about HyperNormalisation https://youtu.be/Gr7T07WfIhM https://youtu.be/Gr7T07WfIhM From wiki: It argues that following the global economic crises of the 1970s, governments, financiers and technological utopians gave up on trying to shape the complex "real world" and instead established a simpler "fake world" for the benefit of multi-national corporations that is kept stable by neoliberal governments
- jack_riminton 21d agoReminds me of Plato's Allegory of the Cave So I don't think it'a new thing, but maybe it's getting worse https://en.wikipedia.org/wiki/Allegory_of_the_cave https://en.wikipedia.org/wiki/Allegory_of_the_cave
- shrubby 21d agoYes, it's awesome and exactly what I had in mind. The century of the self must be recommended also.
- srean 21d agoRemember Orion and Rocky https://www.dogmanray.com/true-stories/orion/ https://www.dogmanray.com/true-stories/orion/ https://greatergood.com/blogs/news/heroic-dog-rocky-saves-63-lives-in-himachal-pradesh-landslide https://greatergood.com/blogs/news/heroic-dog-rocky-saves-63... It would have been more apt if his name was Sirius. Sadly it's not uncommon to see teenage and young men groups to seek out puppies and pregnant strays to stone to death in Himachal and Uttarakhand (two states in Himalayan India). Properly vaccinated they can be protectors.
- ChrisMarshallNY 21d agoI remember in Africa, in the late 1960s/early 1970s, being taught in social studies, that Ethiopia was at risk for famine. They discussed that many farmers raised sheep and goats, which have a drastically different impact on the environment, than cattle (it has to do with how they eat grass -they pull it out by the roots, while cattle clip it). Not long after that, Ethiopia was in the news for... anyone? Lots and lots of ignoring scientists. Nothing new here. Cassandra
- gizajob 21d agoThis isn’t to refute your point… but do you also remember when scientists in the 1970s were panicking about global cooling and an impending ice age?
- ChrisMarshallNY 21d agoNo. I heard global warming. The cooling was from nuclear war.
- regularfry 21d agoActual cooling was from industrial emissions, but that was over by the 1970s. It being something to panic about at that point was a media amplification or a contrarian position, precisely because it was contrarian, not representative of scientific opinion at the time.
- Symbiote 21d agoSome scientists, amplified by journalists. Other scientists at the time were predicting warming. https://www.reddit.com/r/skeptic/comments/1hajzg9/here_is_the_infamous_newsweek_articlecover_from/ https://www.reddit.com/r/skeptic/comments/1hajzg9/here_is_th...
- p_j_w 21d agoThis is a common misrepresentation that deniers use to rationalize their unscientific position. The vast majority of the science, even in the 70s, stated that global warming was our future, not global cooling.
- haunter 21d agoThe Scablands were terraformed by a series of GLOFs (Glacial lake outburst flood) like this when deglaciation started at the end of the last ice age. Just imagine it on a thousand times bigger scale >During the last deglaciation that followed the end of the Last Glacial Maximum, geologists estimate that a cycle of flooding and reformation of the lake lasted an average of 55 years and that the floods occurred dozens of times over the 2,000 years between 15,000 and 13,000 years ago. U.S. Geological Survey hydrologist Jim O'Connor and Spain's Museo Nacional de Ciencias Naturales scientist Gerardo Benito have found evidence of at least twenty-five massive floods, the largest discharging about 10 cubic kilometers per hour (2.7 million m³/s, 13 times that of the Amazon River). https://en.wikipedia.org/wiki/Channeled_Scablands https://en.wikipedia.org/wiki/Channeled_Scablands https://en.wikipedia.org/wiki/Missoula_floods https://en.wikipedia.org/wiki/Missoula_floods Also it's interesting if you start reading about Native American flood stories, these were not just tales or legends but telling actual historic events that the ancestors experienced. https://en.wikipedia.org/wiki/Missoula_floods#Early_flood_stories_and_postulates https://en.wikipedia.org/wiki/Missoula_floods#Early_flood_st...
- oldsklgdfth 20d agoThere is some footage on youtube[0] that provides an aerial view and some perspective on the scale of this thing. From rock climbing, I have a sense of erosion features and their scale. Turbulent flow can carve out huecos in sandstone. They look like someone used a 2ft ice cream scooper on the rock. Now trying to scale up that model to the size of scablands is hard to wrap my head around. This is one of the few interesting things I've learn from the rogan podcast. [0] https://www.youtube.com/watch?v=RopVmgqbt20 https://www.youtube.com/watch?v=RopVmgqbt20
- alkonaut 21d agoIs it possible to avoid these risks in mountainous areas? How many people are living in valleys downstream from lakes with these risks? If one simply concluded that with current climate changes, it's not safe for humans to live under that risk, how many villages and cities would find themselves uninhabitable all of a sudden?
- dredmorbius 20d agoNot readily. The events, even with increased frequency, are relatively rare (perhaps a few times a decade), quite sudden, utterly overwhelming, and destructive to virtually everything in their path. The only assured safety practice would be to keep out of the danger zone entirely, and even this is challenging: - There's very little habitable or arable land, and much of that is in river valleys (e.g., in the heart of the risk zone). - Many mountainous regions are poor, and Nepal particularly so. Governmental and institutional resources are highly constrained, corruption, opportunism, and risk-taking behaviours are common. - It's not possible to construct around the risks, as even the most robust structures are utterly demolished. Post-incident imagery shows bare land scrubbed clean near Gyirong Port, for example. Underground shelter might be possible. But ... - Response times are on the order of seconds to minutes. The elapsed time from the glacial collapse (captured by seismometers) to the debris wall striking Gyirong Port was roughly seven minutes. That's about as much time as would be necessary to climb to a safe(r) elevation or enter an underground shelter. Even then, survivors would have to wait to be dug out, potentially days or weeks later. - Flood run-ups of as high as 800m (2,6000 ft) were reported within 7-8 km of the start of the incident. Even further down the river valley flood depths hit 9m (27 ft) within 30 minutes. Depending on local topography it would be necessary to move a considerable horizontal distance to reach a safe vertical elevation. Though there's an inverse relation between narrowness of a channel and the direct kinetic risk, in the case of this event, even a fairly broad floodplain would have presented considerable risk, and refuge structures would have to be exceptionally robust to survive and provide protection. Monitoring of potential risks, advanced warning (that is, of a potential situation rather than a current one), and evacuation of the affected area would be necessary. Anything constructed within the risk area would have to be seen as a sacrifice zone. Ironically the Gyirong Port was substantially rebuilt this past January following similar, though lesser floods about a year ago which wiped out the Friendship Bridge between China and Nepal. Infrastructure such as roads and bridges might be elevated above river level, but would otherwise have to be rebuilt following events. Advance warnings are disruptive and often turn out not to reflect a manifest threat. With time, public and business response tends to be to deprecate and ignore such warnings. The region has a literacy rate below 70%, as well as being both an international trade route and tourist region, further complicating communications, awareness, and compliance with emergency preparation and response efforts. This isn't to say that nothing can be done, but there are no easy choices, and local poverty will make even modest efforts challenging.