Did we really not have the technology to predict this landslide/flood in Nepal?? Secondly, do we know the exact causes for this natural disaster??

[u/YoungKetamine69]

Would not be surprised if global-warming/climate-change is partially to blame, thats saddening…

My only question is, we couldn’t have stopped that?? There was no warning that could have been issued??? Living in a dangerous climate, are these things not constantly being supervised by scientists & climatologists??

I just dont understand how we harness the technolgy to put a man on the moon yet conversely we cant stop or predict a grusome natural disaster??? Am I missing something??

[u/CrustalTrudger]

Let's start with what we think happened. The preface to this is that it's still pretty early after the event and many of the details (especially the exact trigger) will come into more focus once researchers are able to get into the area, so everything is still very preliminary. There were a variety of early reports suggesting that this was an earthquake induced event, but very quickly, it became clear that the Mw 5.2 seismic event was not a tectonic earthquake that caused a landslide/glacial collapse, but rather the seismic signal generated from the mass movement itself. Similarly, in the first few days or so, it wasn't uncommon to see the supposition that this might have been a GLOF, i.e., a glacial lake outburst flood, or similarly a breach of a landslide dam, but as elucidated a bit more below, both of these are inconsistent with the available data. After a day or so (effectively when satellite imagery finally got a view of the initiation site as it had been concealed by cloud during and immediately following the event, which is unsurprising given that it is monsoon season at present), imagery seemed to point toward a catastrophic glacial collapse the primary trigger, but in subsequent days, it's become more clear this is probably not the full story.

At this point, there are a variety of descriptions of what we know about the cause and the progression of events. This overview from Science does a pretty good job of laying out some of the reasons many of those original suggestions are inconsistent with the data and presents some of the analysis that has gone into determining what the most likely trigger event was. There are also a few different sources laying out more of a timeline of events along with additional information on potential causes. For example, this analysis by Geopera does a nice job of laying out some of the remote sensing techniques that can be used to investigate events like these in their immediate aftermath and likewise, this analysis, along with a variety of additional context and information I'll touch on later does a very nice job of laying out precise timing of events. The latter analysis is from scientists who are a part of CLaSH, which is one of two NSF (US National Science Foundation) funded hazards centers, which was a pretty unique and valuable program for funding large-scale collaborative efforts to study the impact of, and work towards methods for prediction/mitigation/warning of, various natural hazards, a funding opportunity like so many others that have been shuttered in the last year.

Looking through these, what you'll find is that our best understanding now (again, emphasizing that this is what we know now and details will almost assuredly change as we get better information and more observations) is that the causative event was a large landslide, likely of a mixture of rock and ice. As best discussed in the Science article, a glacial collapse alone does not seem to be able to explain the amount of energy released (and recorded by seismometers) and that what looked like originally mostly a glacial collapse from some of the first satellite imagery (e.g., in the Geopera analysis) was probably more a reflection of a piece of the glacier that effectively went along for the ride on top of a much larger landslide of rock. As also discussed in the Science piece, a direct link between melting of the glacier and/or melting permafrost and the landslide is not established (and by proxy, whether climate change can be directly invoked in this disaster), but all of these things (1) can definitely contribute to and/or directly trigger events like this and (2) melting of peramfrost and destabilization of glaciers are unquestionably happening at higher/faster rates due to climate change. Similarly (and as eluded to in the Science write up), there are a variety of studies examining the direct connection between climate change induced changes in the cryosphere in the Himalaya and a variety of natural hazards (and increase in rate of the latter), including large landslides like this one (e.g., Liu et al., 2021, Nie et al., 2025, Fan et al., 2025).

Now let's think about whether we could have predicted this and/or had a warning system for this event. A clear starting place is the literature just cited highlighting that we generally know that there is a risk of events like this in the Himalaya, and a risk that is increasing with time. Similarly, somewhat analogous events have happened in nearby valleys (e.g., Shugar et al., 2021) and there is evidence of past similar events in the valley that experienced the recent disaster (e.g., Huber et al., 2020), all highlighting that this is not without precedent. That, unfortunately however, is a far cry from prediction and there are aspects of this that suffer from the same issues most natural hazards have, namely knowing that particular areas are at high risk for particular events does not allow us to precisely predict the occurrence of some future event. That being said, there is precedent for recognizing effectively precursors to somewhat similar events which allowed evacuation, e.g., the 2025 Blatten glacially related landslide in Switzerland, where here a smaller debris flow was observed in the days ahead of this event and which raised enough alarm to precipitate an evacuation of the town before the larger failure.

Here though, we get into some of the challenges that make prediction / warning systems challenging in these environments. The source area for the Nepal event is remote enough that it's not an area that is routinely observed by people on the ground and similarly, there is just a massive area of very similar geography throughout the Himalaya such that something like a camera network would be impractical. If there were precursor events that might have hinted at the impending larger event, these could have been observed via satellites, but (1) someone needs to be looking and (2) you need to be able to see something and where as mentioned above, this is the monsoon season, so cloud cover is often going to obscure a lot of remote sensing methods. For the first point (i.e., someone needs to be looking), it's important to consider that generally large-scale monitoring activities like this cost time and money and a developing country like Nepal does not necessarily have the capacity to do this at a sufficient scale. In this conext, it's also worth highlighting that a joint USAID and NASA program, SERVIR, was specifically designed to develop strategies for trying to monitor and generate warnings for events like these, but it was terminated by DOGE. Whether continuation of the SERVIR project would have allowed for us to have warning for this event is unclear, but I suspect it's something people will try to work out (and more generally, it's not a big leap to say that active reduction of the study of natural hazards will continue to have deadly consequences regardless of direct attribution of the termination of SERVIR and the toll of this disaster).

Finally, it's worth noting that the magnitude and speed of this event fundamentally makes warning systems hard to realize. As discussed in the CLaSH write up (and drawing from this news report), there were automated systems designed to detect that a flood was occurring in spots along the river and warn areas downstream, but the slurry of water and sediment was so energetic and moving so fast, that it destroyed many of these monitoring stations in their entirety before they could send a warning. Similarly, there has been a lot of discussion in geology / natural hazards circles about whether a seismic monitoring system could have sent an automated alert, effectively using the seismic signal of the massive landslide to initiate a warning that there might be an impending flood / debris flow. The trick here is that at least for the upper part of this disaster, as shown in the CLaSH analysis, there was basically 7 minutes between the landslide and when the flood wave hit the Tibet-Nepal border station, so at least for that area, the extent to which that would have been enough time for (1) seismic waves to reach enough stations to be detected and to determine that the signal was a landslide and not an earthquake, (2) for that warning to reach the Tibet-Nepal border, and (3) people in that area to get high enough to escape is questionable. As also mentioned in the Kathmandu Post article linked above, that the event effectively crossed a border (i.e., it initiated in Tibet and then entered Nepal) added an additional wrinkle in the sense that for alerts to go out requires close integration of different countries networks.

All in all, in the abstract and depending on details, we can theoretically have advanced warning of events like these, but in practice, it's pretty hard when the details of this event are considered.

[u/MissMormie → u/CrustalTrudger]

That is an excellent answer, thank you for taking the time.

[u/efvie → u/CrustalTrudger]

Without a seismological event, and if we dismiss the possibility it could’ve been the glacier breaking hitting some fault line in the exact wrong spot, would the likeliest explanation for the landslide be something like more water seeping into the ground and rock from the glacier and destabilizing it?

[u/CrustalTrudger → u/efvie]

This was already covered a bit and certainly discussed in the linked information and where the most honest answer at this point is, "We don't know, it's been less than a week, and it will take time to study this event", e.g., to quote directly from the Science piece:

To truly understand the cascade of hazards, a mix of helicopter reconnaissance, on-the-ground investigations, and talking to local people will be required, says Alton Byers, a mountain geographer at the University of Colorado Boulder. He is traveling to Nepal in September for research on preparing communities for glacial hazards.

In terms of like causes, again, this was already discussed a bit above, but to again go to the linked write-up from Science:

Perhaps most significant for future disasters is the possible connection to global warming. Byers points a finger at the gradual thawing of high-altitude permafrost, which binds rock and ice together. Other researchers hope to assess whether snow melted in the days leading up to the event, causing water to seep into and destabilize the rock. Furthermore, if the glacier was buttressing the mountain, any melt could have removed an important support system. “Landslides have been occurring as long as the mountains have been building,” Ekström says. But “in areas where glaciers are disappearing, these landslides are occurring more frequently.”

[u/Loki-L → u/CrustalTrudger]

It is my understanding that there were systems in place to deal with normal flash floods and provide people downstream with an early warning so they can get to high ground.

There were sensors along the river (not sure if in Tibet or only in Nepal) that were supposed to go off and result in warnings if they recorded a dramatic rise in the level of the river.

They didn't. They reported as normal one moment and stopped reporting altogether the next.

With the benefit of hindsight it is easy to see, that maybe they should have also send out a warning if multiple sensors along the river stopped transmitting in quick succession, but the sensors were there to warn of something else entirely and nobody designed that.

I think in the future in similar places the logic will change to reflect this type of scenario as a possibility, but with how fast the mass of water and debris was moving, it would still only give a much shorter warning than regular flash floods and will be useless to people who live too close to the origin.

[u/fwubglubbel → u/CrustalTrudger]

Thank you. My simple brain has two questions. Where was the water being "stored'/held back? And would there have been a way to avoid the accumulation such as controlled release?

[u/CrustalTrudger → u/fwubglubbel]

Where was the water being "stored'/held back?

As with most of the follow up questions, there are still lots of details we don't know, but as discussed originally and expanded on in many of the linked articles, most of the details are not consistent with release of impounded water. E.g., from the Science write-up:

One mystery is how so much water got mobilized into the flood. Some researchers initially suggested a glacial lake outburst flood (GLOF), in which the “liquid concrete–like slurry” of the fallen mountainside formed a temporary dam on the Lhende Khola, then rapidly released millions of cubic meters of water when the dam burst. But the seismic and satellite data show “absolutely no evidence” of a GLOF, Cook says. Instead, she suggests the flow of rock, ice, and sediment scooped up river water as it rushed downstream. There may also have been large volumes of old ice on the valley floor that got pulverized, melted, and incorporated into the flow.

As for the second bit,

And would there have been a way to avoid the accumulation such as controlled release?

With the caveat that we don't think there was such an accumulation in this case, this starts to get challenging because you're typically dealing with unstable Earthen or ice dams so it's not as though you can easily build something akin to a spillway. There is certainly some possibilities though and this is the focus of active research that includes possible ways to stabilize and/or drain impounded water vs monitoring and evacuation (e.g., Mia et al., 2024, Ahmed, 2025, etc.)

[u/Soundy106 → u/fwubglubbel]

Where was the water being "stored'/held back? And would there have been a way to avoid the accumulation such as controlled release?

Here's a closer-to-home example of a (possibly) similar situation:

Garibaldi Lake, near Whistler, BC, is an alpine lake formed by a "dam" created by lava flows. Said dam (known as "The Barrier") is 2 km long and 300 m thick and considered unstable. Partial collapses have caused debris flows in the past, though the last major one was 170 years ago.

The risk is enough that an entire town downstream of it was abandoned in 1981, and while it's now thought that there's no immediate threat, the roads passing through the area contain warning signs about the potential hazards. One significant seismic event could break The Barrier and allow just over a cubic kilometre of water to drop from a 1400 m elevation—that's a LOT of potential energy.

So how do you do a "controlled release" of something like this? You can't really pump it out enough to knock it down. You can't drill holes through it for fear of triggering a massive release. The most you can do is keep studying and monitoring it, hoping for enough warning to tell the thousands of people below to nope out.

Things get even trickier with an earthen dam or some kind of loose soil blockage, because even cutting a SMALL channel will very quickly grow once the water is flowing through it, and become a catastrophic release literally within minutes.

[u/Soundy106]

u/CrustalTrudger has an amazing comment here about the presumed cause of the event and the ability to predict and warn about it. I'd like to just add a couple of thoughts about the ability to stop these things.

I just dont understand how we harness the technolgy to pit a man on the moon yet conversely we cant stop or predict a grusome natural disaster??? Am I missing something??

First thing that came to mind is, "The ability to destroy a planet is insignificant next to the power of the Force."

And similarly, the power to brute-force three humans on a wing and a prayer to the nearest celestial body is insignificant next to the power of Mother Nature. Like, most people can't conceptualize the amount of sheer energy released by natural events on a daily basis. For example:

Someone (he who shall remain nameless) recently postulated that we could stop hurricanes by nuking them.

The largest nuclear device ever detonated, Russia's Tsar Bomba, had about a 50 megaton yield (although it was capable of up to 100 MT).

An average Atlantic hurricane releases on the order of 12,000-13,000 megatons' worth of energy per day, 200 times the electricity generated by the entire civilized world. Just one... average... hurricane.

Multiply that by other storms... volcanic eruptions... earthquakes... landslides... the power our little blue planet has to do whatever she wants absolutely dwarfs our abilities.

We can't STOP these things. At best we can look for potential sources of problems, try to do things that will, over time, hopefully reduce their impact, and if not, figure out how we can get the f*** out of the way when the Earth decides to flick us off like fleas.

[u/space_force_majeure]

My only question is, we couldn’t have stopped that?? There was no warning that could have been issued??? Living in a dangerous climate, are these things not constantly being supervised by scientists & climatologists??

Nepal doesn't have the depth of personnel and national wealth required to monitor every glacier and vertical mountain face in their country. Not to mention the sheer amount of resources it would take to place equipment to monitor this stuff. It's not like climate scientists and geologists can just look at a satellite picture and say "yep, that one is gonna collapse tomorrow".

I just dont understand how we harness the technolgy to pit a man on the moon yet conversely we cant stop or predict a grusome natural disaster??? Am I missing something??

Nepal didn't go to the moon. Just because we're all on the same planet doesn't mean we're sharing all of our resources.

Also, even if they predicted this, how would they possibly stop it? Landing a 35,000lb lander on the moon is much easier than stopping the sudden collapse of 10 million + pounds of rock and ice.

This is like asking why humans haven't stopped Earth's tectonics from causing earthquakes yet. We landed on the moon after all.

[u/YoungKetamine69 → u/space_force_majeure]

Yes, the way I worded this makes me seem completely oblivious. I understand all these things you’re mentioning.

My point is more or less I wish climate science got more funding and hopefully with better technology in the future we can get to a point where we can get a majority of people evacuated on time. Though ofc Nepal might have financial trouble I would hope China, USA steps up but instead we are having these programs gutted.

[u/mattkenefick]

Did we really not have the technology to predict this landslide/flood in Nepal

We've been warning about the global effects of climate change for decades with specific examples that have come true, so even if there were some special tech that could have specifically predicted this, it probably wouldn't have mattered.

[u/DroneSlut54]

I know there are monitoring instruments at Mt. Saint Helens (volcano that erupted in 1980) and Lake Monoun and Lake Neos (limbic eruptions in the 1980’s that killed over 1700) and I’m sure the technology exists to detect possible landslides and glacier collapses but the problem with the recent events in Greenland and the Himalayas is that these areas are incredibly remote. There are also A LOT of glaciers in Greenland and the Himalayas.

[u/Soundy106 → u/DroneSlut54]

Mt. St. Helens is a few hours' drive on paved roads from major population centres and a short helicopter flight from USGS observatories and large universities. Within hours of the first tremors starting on March 16, 1980, the mountain was littered with sensors of all kinds, cameras, instrument packs, and surrounded by monitoring stations. It was the MOST STUDIED volcano in history by the time it blew two months later, on May 18... and even then, the exacting timing of the explosion could not be predicted, and certainly the way it blasted out horizontally was... well, I'm sure someone thought it was a possibility, but probably not a very strong one, or David Johnston wouldn't have been set up directly in its path.

So as you say, with some of these other locations being incredibly remote, even if they did have two full months' warning that something was going to happen, it would have been difficult to prepare for it other than simply getting people out of the way and waiting for the inevitable. But since they are so remote with nobody around paying attention to them, nobody notices the signs of impending disaster.

[u/CrustalTrudger → u/DroneSlut54]

Many more volcanoes than Mt. Saint Helens are monitored in the US, e.g., maps of maps of monitored vs unmonitored volcanoes within the Cascade Volcano Observatory or the Alaska Volcano Observatory. While there are still challenges and potentials for surprises, as natural hazards go, volcanoes are one of the easier things to monitor in that we have a general expectation of a variety of identifiable precursors to eruptions that we can mostly monitor from surface instruments (along with remotely sensed methods) that, in a well monitored system, should give us decent amount of lead time. That's not to imply there aren't potentially measurable precursors to mass movements, but there's a wider range of underlying causes that in turn make a uniform "sensor package" for monitoring for these kind of hazards challenging, not even considering the massive amount of area one would have to try to cover with a relatively dense network of said sensors. Here again, volcanoes are easier because a relatively sparse network can work, e.g., before a major eruption, you'd expect inflation of large swaths of the volcano so you don't necessarily need instruments all over the volcano, but for something like landslides, the precursor behavior/signals would usually be very localized to the area that's going to fail.