Worst-case glacial lake flood scenarios in a transboundary Himalayan basin 2022

ttotetsu about 3 hours ago 25 commentsRead Article on nhess.copernicus.org

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ChiperSoft•about 3 hours ago

Context: https://www.cnn.com/2026/08/26/world/live-news/nepal-flash-f...

delichon•about 2 hours ago

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.

ghastmaster•about 1 hour ago

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•32 minutes ago

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.

ANH•26 minutes 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.

suzzer99•22 minutes ago

I wonder if the river went dry first, like the water receding off into the horizon before a tsunami?

ghastmaster•16 minutes ago

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.

colechristensen•7 minutes ago

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.

markdown•about 2 hours ago

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.

arjie•about 2 hours ago

150 confirmed with 47 Americans? Surprising fraction. Mountaineers or that area is popular for some reason?

adelie•about 2 hours ago

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•about 1 hour ago

Likely the tourists are better accounted for than the locals. Numbers are likely much higher :(

markus_zhang•about 2 hours ago

Nepal is popular for Westerners I think. Maybe for religious reasons?

janhaa•about 2 hours ago

i understand it as 150 dead, with more people missing, of which 47 are americans.

suzzer99•21 minutes ago

I feel like I've easily seen more than that get swept away in videos.

segmondy•about 2 hours ago

Way too early to get an accurate count

markus_zhang•about 2 hours ago

I have watched a few and they look like the four horsemen TBH.

inasio•about 2 hours ago

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]

https://en.wikipedia.org/wiki/1970_Huascar%C3%A1n_debris_ava...

raz32dust•about 1 hour ago

It almost certainly is. Just too early right now.

jvanderbot•about 2 hours ago

I believe this is how the Hudson Bay was formed, in what must have been quite a sight.

ghastmaster•40 minutes ago

Hyperbole?

>Much of the landform has been shaped by the actions of glaciers and the shrinkage of the bay over long periods of time

This would support your notion. Albeit ridiculous.

>Finally starting in the Late Ordovician and continuing into the Silurian did the gradual regional subsidence of this part of the Canadian Shield form the Hudson Bay Basin

This would not.

I cannot decide whether to laugh, or downvote your comment without more context. That I did some research and learning to decide to comment instead leaves me happy and satisfied that your comment was not completely worthless.

ref: https://en.wikipedia.org/wiki/Hudson_Bay

madaxe_again•about 2 hours ago

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.

https://earthquake.usgs.gov/earthquakes/eventpage/us7000tbwb...

ghastmaster•22 minutes ago

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.

metalman•about 1 hour ago

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

https://www.youtube.com/watch?v=-UoyIV6oZEc

bamboozled•about 1 hour ago

Wrong link