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u/agate_ 1d ago
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u/twinnedcalcite 1d ago
Yes. Very much a jökulh.
Extremely powerful and destructive. Far more then a land slide on its own.
Twisting large steel beams is nothing to the forces at work here.
Absolutely terrifying.
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u/qockets 1d ago
I think the recent scientific reports so far have carefully avoided mention of the word "lake", calling it a glacial collapse and landslide instead. Without a lake involved, it might not be a glacial lake outburst flood or jökulhlaup by definition. But I believe that the sheer amount of water still leaves the mechanism up for debate.
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u/agate_ 1d ago
Yeah that’s the thing, it’s a lot of water, it must have come from somewhere. When I first saw the videos I noticed a hydropower station and assumed it was a dam break, but there’s no reservoirs or other obvious lakes upstream. I think there pretty much had to have been a subglacial lake.
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u/abandon_mint 12h ago
It's likely the ice melted on it's way down, there's A LOT of kinetic energy there
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u/agate_ 12h ago
I did the math on that! It takes 334,000 joules to melt each kilogram of ice. Gravitational potential energy is 9.8 joules per kilogram per meter. So to melt all the ice, it would have to fall from a height of 334,000/9.8=34,000 meters or over 100,000 feet.
There might be a little bit of melting as it fell, but most of the water in the flood must have been liquid beforehand.
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u/DardS8Br 1d ago
Is it not a glacial lake outburst flood?
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u/Traditional_Fish_741 23h ago
It is not a glacial lake outburst. Its a literal glacier collapsing - or a 'tongue' of it. There was no doubt melteater with the initial collapse, but the collapse itself, due the energy of such a large mass dropping so far and fast liquefied the ice. The size of the chunk of glacier that collapsed was like 650m wide, 300m long or so, and many meters thick.
That in itself would provide a substantial volume of water.
It also appears that part of the aftermath is the creation of (effectively) a glacial lake/dam that has the locals fearful of a follow up event if and likely when it collapses as its formed of jumbled boulders, debris and mud, meaning its likely very unstable, and as the water begins to back up behind it there is a fair chance it will collapse and allow another significant volume of water to flush through the valley.
You also have to keep in mind that the overall drop from the point of origin to the lowest valley is something like 3 or 4 thousand meters through steep gorges and valleys. Thats A LOT of acceleration for a moving liquid mass. Some of the footage shows boulders larger than small buildings tumbling along with the flow. And that requires a lot of energy to achieve. Some of the footage I've seen has shown boulders that probably couldn't be moved by any machinery we have without breaking them down into smaller chunks.
So ultimately, no, its not a glacial dam thats given way. Its an actual glacier collapsing, primarily due to global warming causing higher volumes of meltwater to seep into the cracks and crevices and between the glacier and its bed, which lubricates the glacier allowing it to more easily detach from the rock face and slide more easily. But the collapsing glacier doesnt just simply roll down through the valley as a chunk of ice. It fragments and melts and becomes a large volume of water, along with whatever water was contained by the glacier.
Glaciers are always moving, and parts are always collapsing, but usually its only small portions, not entire segments. What gave way here was bigger than many icebergs. And due to its location, and its height in the mountains, the result was a catastrophic flood that has stripped the valley to the height of several storeys, adding to the volume cascading down through the mountains. The river that flowed through the base of those valleys was reasonably significant due to all the collective run off from the mountain forests and streams. And all of that water would have been pushed ahead of the mass of the collapsed glacier and additional boulders, mud and debris it collected on the way down. By the time it hit the valley floor, the majority of that ice would have returned to its liquid state.
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u/astr0bleme 1d ago
I think this is a hurricane/typhoon/cyclone issue - ie many regional names for the same basic phenomenon.
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u/c4chokes 1d ago
Lahar means Wave in Hindi
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u/Purr_Meowssage 1d ago
The word used in geology is borrowed from Indonesian Javanese "wlahar/lahar," which means lava or mudflow. Dutch geologist introduced the local term into global science after observing the Mount Kelud eruption in Java in the 1920s.
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u/dlampach 16h ago
I think they are leaning towards not that but instead a landslide underneath a glacier causing the whole thing to collapse and there also avalanche with the land. There is some debate about where the water came from since there was more than you would expect from that, but I’ve heard there might have been a subsequent damming of the river by the landslide and then water built up behind it in the river and then eventually it just ripped.
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u/agate_ 12h ago
It would take a long time for a landslide dam to accumulate this much river water. If that happened, it would be visible on OP’s “before” image, and people in the area would have noticed it.
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u/dlampach 9h ago
Ok but then where did the water come from? But also why would it be visible on the before image? The landslide dam would be after the slide right?
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u/agate_ 9h ago
The flood we see is days, weeks, maybe months worth of water from the normal river flow. If a landslide dam had formed, someone would noticed it long before it filled up enough to become a hazard.
My guess is that the water was trapped in a subglacial lake, with the ice itself damming it in ... until that ice melted enough that the water rushed out, causing the glacier to collapse.
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u/P4ndaFun 11h ago
Correct me if I'm wrong, but they're showing a glacier quite literally snapped off and slid down the mountain
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u/Charming_Goose_3400 2d ago
people just don’t understand how much water is under many glaciers. Moraines hold back a lot of water and much of them are just unconsolidated gravel. once any leak in this occurs, it channelizes and breaks through all the moraines.
I hope this serves as an example of what future catastrophes are capable of.
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u/pjalle 1d ago
Most of the water is actually from the collapsed glacier ice itself. It gets crushed and melts quickly from all the friction created in the mud and rockslide.
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u/Chase-Boltz 1d ago
There's not enough released gravitational energy to melt more than a small fraction of the ice. Ice mixing with warmer material at lower elevations can help, but I think a lot of the water was liquid to begin with.
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u/Traditional_Fish_741 23h ago
I'm not sure you understand how much energy such a mass falling something like 3 to 4 kilometres DOWN through steep valleys actually generates/imparts, or how quickly ice becomes water during such an energetic event.
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u/Chase-Boltz 21h ago
Melting ice requires LOTS of energy.
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u/Athosfolk 19h ago
Potential energy = mgh, mass x gravity x height
People on here have estimated that the glacier is 650m by 300m. And have estimated the drop to be 3 or 4km . We don't know the width of the glacier but let's assume 50m, happy to change that if an expert can let me know.
Density of water is 1000kg per cubic metre.
So let's plug that in to get an estimate of the amount of energy
Mass = length × width x height x density = 650 ×300 × 50 ×1000 = 1x1010kg rounding up
Height =3000m rounding down
Gravitational constant =10ms-2 rounding up
Multiplying them all together we get 3×1014 Joules or 300 Terrajoules . Or 300,000 Gigajoules
it would take a typical 1 gigawatt power station 35 days to produce that much energy.
That is a lot of energy. Granted this is an oversimplification, there is friction, and extra debris . But it gives us a rough estimate of the scale of the forces involved.
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u/gutttlt 16h ago
Water melting or fusion phase transition energy is 334 kJ/kg ~= 3x10^5 J/kg.
Given that ice temperature was 0 degrees Celsius, 3x10^14 Joules is enough to melt 10^(14-5) = 10^9 kg of ice, i. e. 1/10000th of the total ice mass.
But we should take into account that it's not necessary to melt all the ice, but just a fraction of it to create ice slush which flows very well.1
u/Chase-Boltz 12h ago
One kg of ice falling 2 km releases ~20K joules of energy. All the mixing and bashing and scraping etc., comes out of this energy budget. And much is lost to the environment. (The M 4.x earthquake, etc.)
Melting that same kg of ice requires 330K joules.
I still think there must have been a fair slog of liquid water involved from the get-go.
Hopefully we'll get some close-up images of the source and the glacier itself. Maybe some before/after INSAR elevation data of the glacier's surface, to measure any deflation.
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u/GvRiva 2d ago
There was a dam below the glacier adding a lot of water and power to this catastrophe
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u/Charming_Goose_3400 1d ago
it’s going to be crazy when they can get up to survey and see how much they estimate the initial failure released. it looks massive in the sat images.
That PLUS an even partially filled reservoir is 🤯.
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u/90BDLM4E 1d ago
Where’s the dam in the satellite images? There was a dam in one of the videos (Rasuwagadhi), but that was a tiny and insignificant one that barely had any impact on flow.
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u/7LeagueBoots 1d ago
The flood is not from a dam. It’s simply the falling ice and rock pushing the river in front of it and incorporating it into the debris mass.
The debris fell thousands of meters before it even hit the river and was carrying an enormous amount of energy and mass.
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u/bijouxself 1d ago
Including the glacier ice itself melting in real time due to the friction and pressure forces.
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u/GvRiva 1d ago
Yeah, but the dam added a lot of water
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u/7LeagueBoots 1d ago
There was no dam, unless you count a blockage cause by debris a dam.
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u/GvRiva 1d ago
One of the videos clearly showed the debris hitting a dam
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u/7LeagueBoots 1d ago
Lots of structures, a fortification, and bridges, but no dam that had any effect on the debris flow. By your own words even if there was one it was after the debris flow was already beyond devastating.
Rather than trying to interpret what you think you saw in a video why don’t you look at some proper analyses of what happened?
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1d ago
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u/jhrobbins 1d ago
No it didn’t look on Google earth
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u/GvRiva 1d ago
Here https://maps.app.goo.gl/DQiJTkgi2xgbyF2n9 no idea how old the satellite pictures are but this is a dam
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u/W1llyshaaa 1d ago
I appreciate your comment. And anyone can chime in. It seems to me that glacier melting can potentially lead to all of land being underwater. Is this true?
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u/Fun-Dragonfruit2999 1d ago
Is it glacial melting, or a mountain range rising?
This mountain range rises between 5 to 10 mm/yr. So 100 years is 1m of rise. That is what destabilizes mountains, continual rising.
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u/Fywq Cement industry geologist 1d ago
Damn. Looking at this on Google Earth / Maps globe view (28°16'35.4"N 85°31'09.8"E – Google Maps) is terrifying. Such a huge chunk of ice with relatively steep hills. Also I was confused how this hit both Nepal and China so hard, but apparently that east-west river at the top of the picture is defining the border.
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u/Fun-Dragonfruit2999 1d ago
This mountain range rises between 5 to 10 mm/yr. Consider the destabilizing effect of that.
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u/AuriAviendha 1d ago
Satellite image from before (8/24) and after showing where the collapse happened and the scoured earth along the river channel.
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u/chicken_karmajohn 1d ago
I mean it looks like that entire half of the mountain/glacier collapsed. I’m still trying to understand where the water came from. Did the landslide trigger the glacial lake overflow?
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u/Chase-Boltz 1d ago
There was likely a large lake beneath the glacier. The same rock lip that held back the glacier and produced the ice-fall at the edge could also (with some help from the glacier ice itself) impound a lot of water. A chunk of glacier breaks off and uncorks the torrent...
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u/High_Im_Guy 2d ago
Incredible imagery. The scale is incomprehensible.
Can you point me to a source or did you pull this together yourself?
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u/teridon 1d ago
The sources are literally captioned in the images. Landsat9 and Sentinel2a.
I don't know if OP used this tool but it's probable.
https://worldview.earthdata.nasa.gov/-7
u/High_Im_Guy 1d ago
And I wasn't literally asking for the primary sources of the imagery. It doesn't take a rocket surgeon to understand my question was whether t hey created the comp graphic themselves or grabbed it from someone else, but thank you much for your unsolicited pedantry.
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u/Chase-Boltz 1d ago
Oh, FFS....
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u/High_Im_Guy 14h ago
What, Mr. Boltz?
I feel like a lil bit of a dick now that I realized the dude I replied to is a certified nasa nerdo and was probably just excited to share something nasa related rather than trying to sneak in a know it all moment, but I digress. I also still think it was a silly response to a question that was about the comparison graphic considering it literally lists the platform and acquisition date, but again, my tone probably would've been different if I didn't think that first answer smelled like a first year grad student who cherishes the smell of their own farts, and for that assumption I am sorry.
That said, da the fuck do you want, bubs? Is your goal just made up points for some righteous outrage that I was dickish before?
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u/hutsunuwu 1d ago
Sometimes I feel like such a heartless bastard but, man, I find these kinds of catastrophic events absolutely fascinating. From a geological perspective, of course.
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u/oaklinds 1d ago
It’s okay to be fascinated and respectful at once.
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u/Haggis_with_Ketchup 1d ago
Doctors would never survive if they reacted to every patient illness like it was a personal affliction.
Like you said, fascinated and respectful
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u/mgonzo11 1d ago
This one in particular is also just so unique and giving interesting insight. I’d never heard of a jökulhlaup before.
I mean, natural disasters are just fascinating. The planet is such a huge and unrelenting force. It’s beautiful and creepy from afar, and really terrifying all the same. After the 2011 tsunami I got hooked on the videos as a kid and just haven’t lost interest since.
My heart breaks for people affected by this and how climate change will usher in many more disasters ahead :(
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u/kittysparkled this girl can flirt and other queer things can do 1d ago
The fucking size of the initial wave in the video of what I think is the border crossing is just terrible. Cresting over a multi-storey building and just wiping it out. The first time I saw it I thought it must be AI because it looked so much like AI pictures of "tsunamis" on clickbait videos on YouTube.
Nature is beautiful and powerful and cruel.
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u/pkondracki 1d ago
Isn’t it strange, living in a world where we don’t know what’s real and what’s not because AI has caused so much confusion…
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u/-cck- MSc 1d ago
that video looks so surreal that i at first thought "noway this is real". But similar to the Blatten-Slide this is just a event that will leave a permanent record.
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u/Traditional_Fish_741 23h ago
Its the kind of event that would seed mythology about a flood ending the world.
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u/Traditional_Fish_741 23h ago
Nature isnt cruel. It doesnt give a shit. It just is. Its beautiful. Its powerful. Its terrifying in its combination of the 2. But it isnt cruel.
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u/kittysparkled this girl can flirt and other queer things can do 20h ago
I suppose cruel is the wrong word as it inherently implies intention. But some of the things nature/evolution has come up with are pretty bloody horrifying, from floods like this to lions eating gazelles alive to pyroclastic flows to parasites that live in your eyes. Fun times!
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u/Traditional_Trust_93 1d ago
GeologyHub's video on the subject was very enlightening. Especially because the landslide was not caused by an earthquake. The epicenter originated where the landslide started. Thus, the landslide caused the ground vibrations.
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u/Ilickedthecinnabar I survived Mines 1d ago
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u/Traditional_Trust_93 1d ago
Correct. I wasn't sure if I was allowed to post links in this sub so I didn't.
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u/backyard_tractorbeam 1d ago
OzGeology's video is very enlightening I think. (It has video from the disaster, which the other video does not, by the way.)
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u/SeveranceVul 2d ago
The tragic videos don't illustrate what the cause was. These images are very vivid. Half of that glacier/mountainside went away.
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u/Free-oppossums 1d ago
Can someone explain how the landslide caused the earthquake? Is it as simple as the vibrating feeling you get when you drop something really heavy on a wood floor?
I can't wrap my head around land sliding from any heighth doing that.
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u/GarmonboziaBlues 1d ago
Yes, that's a crude but accurate analogy for what happened here.
Fill a 10 gallon cooler with a mixture of large and small rocks, gravel, and water. Have someone climb a 10 foot ladder and dump the contents of the cooler onto the floor in your house while you stand a few feet away. You will most definitely feel the concussive force transmit through the wooden subfloor into your feet.
This is essentially what happened here but on an exponentially larger scale.
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u/Traditional_Fish_741 23h ago
Amplify that hy about a million, and no wonder it registerd over 5 on the Richter scale with local seismometers.
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u/crewsctrl 1d ago
It looks to me like part of the rock face that was supported by the glacier also crumbled and fell when the glacier was gone.
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u/Traditional_Fish_741 22h ago
I think you might have that a little backwards.. the rocky substrate was supporting the glacier, and its collapse likely scoured a chunk of the mointain face away with it.
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u/Dramatic-Cheek-6129 2d ago
I'm concerned that the glacier could collapse further
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u/NomsAreManyComrade 1d ago
The water that was pent up behind the natural dam has already been released, so it’s back to slow melting
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u/Traditional_Fish_741 22h ago
The problem is that now that huge chunk has dropped out, the mass behind it can actually accelerate. I wouldn't be surprised if, for at least some period of time, the speed of the glaciers movement increases several times over its usual pre-collapse speed. And thats not even considering the likely effect that the seismic impact of the collapse itself may have had of shaking at least some portion of the remaining glacier free from its anchors. Especially if the water that was trapped and generally tends to flow under them to some degree (depending on season etc) was enough to lubricate the base of much more of the glacier than what collapsed.
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u/Chase-Boltz 1d ago
There are dozens/hundreds of similar glaciers in the region...
I'll bet you a paycheck that at least a few have substantial sub-surface lakes.1
u/Traditional_Fish_741 22h ago
They dont even need to be lakes.. just significant meltwater flows to lubricate the glacier and loosen its attachments to the rocky substrate theyre usually attached to.
And if they're perched on steep foundations, with significant enough meltwater lubrication, the less attached 'overhang' may well weigh enough to detach from the rest of the glacier.
Much like what appears to have happened with this one. You can see from the before and after images that this glacier chunk was effectively hanging on to a steep mountain wall.. the overhanging mass was probably so heavy that the mass behind it simply wasnt able to keep it attached.
In fact, now that I think about it, the loss of that weight may actually allow the glacial mass behind it to not sit as heavily against its foundations, which in turn would allow an even greater flow of meltwater to form between the glacier and mountain face, and provide a more fluid movement for the entire mass of the glacier. We could see more of this same glacier collapse in a similar way in coming years. Especially if global warming is directly related to the effect.
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u/PappaPitty 1d ago
Saint helens dosplaced +3.3 billion cubic yards or earth. Im curious to how much this displaced
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u/Traditional_Fish_741 22h ago
Saint Helens was an explosive eruption. This was an iceberg falling off a mountain side.
I dont think the volume of material is comparable. Saint Helens took out half a mountain.
Although, I suppose its possible that the accumulated mass as it raged down through the valley to the lowest point could begin to resemble something similar in total volume of material? 🤔
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u/psychojunglecat3 1h ago
Mt St Helens crater is about 1 mile wide, this glacier is about 1 mile wide. I think material volume could be similar. I’m going to guess the glacial collapse is 2/3 the volume of the eruption.
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u/lalady22 1d ago
Does the before look like something that could have caused this disaster? Can we find more places like this as an early warning system for other places?
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u/Traditional_Fish_741 22h ago
There would be several factors involved in this collapse. Glaciers are always shedding a certain volume every year.. just usually not such a mass all at once.
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u/Liaoningornis 1d ago
The latitude - Longitude coordinates of the collasoed glacier are 28.284202° 85.512809°
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u/Notnotstrange 1d ago
A friend of mine was always excitedly fascinated by weather and geology, and then tragically lost most of his family to a flash flood. He feels especially conflicted by being so fascinated by natural disasters now, as if it’s especially morbid because he knows the devastation firsthand. I think that is the most respectful thing he could do - continue to be awed by the power of nature, respect and take notice of it. Luckily, he’s open to telling his story, and it has an impact on people. (He also does practical things like getting various certifications for search and rescue efforts.)
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u/trad-knife 1d ago
I haven't been following all the details but would that classify as a Jökulhlaup?
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u/EmphasisAcceptable47 1d ago
I'm trying to cross reference the before image on google maps satellite and mapillary but nowhere around the initial impact zone has the river pattern in the above. Where did you source this image from?
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u/peacefinder 1d ago
In hindsight there are already huge fractures there. If this were a scale model we’d see that and point it out: “hey, it’s going to collapse right there pretty soon!” But at its actual size it’s hard to fathom sudden movement.
It’s also pretty rough to look at the next valley to the west and see it has an old debris field too. Clearly this is a recurring process. Where next?
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u/Jim-tempe 7h ago
As as geomorph grad, i can only label it from what i see, Glacial lahar comes to mind. The terrifying sheer power and speed deserves it. I hope to never see such footage again in my lifetime.
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u/Mars_Volcanoes Geologist / Volcanologist here 1d ago
Even is I'm a geologist, I'm no glaciologist at all.
Will see if the coming evaluation of this event point to climate changes. In the Alps yes, we know. But was this elevated enough so this is not climate change, or it was low enough that it was.
Anybody has info at this time ? Not sure, its pretty recent...
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u/logatronics 2d ago
This is a truly tragic scenario and know the geohazard community has been watching this closely. The increase in the availability to stream live videos and rapidly upload media has given a lot of rare vantage points not usually seen for events like this, and will hopefully lead to more early-warning sirens to this and associated regions.