Barrier lake continues to pose flood risk, China warns | Hacker News Reader

Barrier lake continues to pose flood risk, China warns

kathmandupost.com

90 pointsr72123 comments

For a bit of context, Juneau Alaska deals with a smaller scale version of this most years. There's a bowl off of the Mendenhall Glacier named Suicide Basin. Each summer that basin gets filled with meltwater, which forms a lake because the glacier blocks the water from leaving the basin. At some point the lake fills with enough water that part of the blockage gives way and the lake suddenly releases.

In Juneau, this is a well-defined basin with well-established dynamics. The city still wrestles with how best to handle this. Recent years have seen higher river levels when the basin releases, and the downstream banks of the Mendenhall River have eroded much faster than people were expecting. The city and individual homeowners are engaged in multiple projects to manage the annual flooding.

In the Nepal case the scale is much larger, and the variables are less known and less stable. This is absolutely devastating to see.

https://www.adn.com/alaska-news/2026/08/12/juneau-officials-...

I completely disagree. The variables in these situations are WELL known. The difference is scale, and in the Himalayas there is no cost effective, completely safe way to deal with them. The hydroelectric potential in that part of the world is the main driver for the continuous build -> flood --> destruction --> build cycle. Obviously, the last event was nothing short of astonishing, devastating and horrific. The worst part is that it will happen again, just differently.

Yes, most of our problems with the shifting climate are not physical, their not engineering, they're nothing but stupid, stupid "social studies". The kind of thing billionaires want to buy their way out of, which they can't, so they do the next best thing: abandon all hope and build their bunkers cause real philanthropy is complex, and real society isn't just something an LLM can dictate and people will just follow.

What do you mean the hydroelectric potential is the driver? Is there a word mistaken?

There is no electricity production?

I think they mean a resource ripe for extraction. There is huge stored gravitational energy in that ice and water up so high, which is also exactly why it was such a disaster.

Potential as in possibility, not as voltage. It's an awkward phrase...

> It's an awkward phrase...

You might even say it's charged.

Potential and actual as in voltage.

Huh? I mean, if you look at the actual damage reports you see quite a bit of energy taken of both Nepal and Chinese grids. Further deduction leads to the obvious conclusion that hydroelectric generation in the district is VERY important.

> > the variables are less known and less stable.

> it will happen again, just differently.

It seems to me that the two of you are actually in agreement. If we had a better understanding of the variables we'd have been able to predict what happened in advance from the reams of satellite data we have.

No. It will happen again the only thing that will change is the amount of water and debris. More or less people will die depending on the incentives to live in the district. Humans should not inhabit those valleys.

That's not a response to what I wrote? If we had a better understanding of the variables then we'd almost certainly be able to leverage all the data we have to warn people in time to evacuate. Similar to how wildfires used to kill a lot more people but these days even in the most fire prone regions you'll almost always have time to get out if you heed the evacuation notice.

I agree with you that flood prone areas are generally a poor choice of place to live but it seems to me that's neither here nor there.

Reminds me of the Fargo-Moorhead diversion project. The Red River flows north through Fargo, which means that down-river portions can ice over in the winter and cause upstream flooding. The diversion project should wrap up soon, and hopefully it works. As I understand it, the city is going to appeal with insurance companies to drop costly flood insurance requirements.

This lake is currently halting any further rescue operations in the area, because the collapse of it threatens to unleash yet another very devastating flood.

As these natural glacial reservoirs have no usual natural outlet, when they go, that's thousands of years of stored water and energy released. Anything that catches it now has those forces to contend with, and freshly-created lakes tend to not hold up very well to being constantly filled while attempting to settle into a stable configuration.

That unfortunately means we have to give up on the people caught in the first flood, as the potential for a second one catching the rescue workers is too great.

Horrible incident. The best we can hope for from this is a greater understanding of the risks associated with living in such an area, and hopefully better geological warning systems will be created out of this.

EDIT: For perspective, the energy released in this event, capable of causing a 5.2 magnitude seismic event to register, would have been equivalent to roughly 30 of the nukes we dropped on Hiroshima and Nagasaki.

> that's thousands of years of stored water and energy released

You make this sound like it matters whether the water accumulated over 10,000 years or 30 days. It doesn't.

Quite, it's the volume water and the speed of release which matter, nothing else.

As a studying geologist, I find such a simplistic reduction to be very absurd, there are many factors which influence how that released energy causes its damage. Are there physical impediments in the way? Are there breaks in the path of flow? Is the environment already used to this amount of water flowing through it suddenly (the evidence of life everywhere says no so no surprise a ton of life gets lost when it suddenly blows through.)

Such a simplistic reduction also does serious disservice to the structural geologists, soil analyst techs, and others in the geological profession whose work focuses on preventing exactly this sort of situation. It's more complex than "Volume and speed."

> there are many factors which influence how that released energy causes its damage. Are there physical impediments in the way? Are there breaks in the path of flow? Is the environment already used to this amount of water flowing through it suddenly

and nothing of what you listed is "how long this particular water volume stayed in its particular location before starting to move" (because energy is energy)

don't lose context of what is complained about, dude.

The point is that if the local environment is used to dealing with X amount of water every 30 days, the life and environment will be adapted to the flood zone. If X amount of water comes once in 10,000 years, this is not the case.

The point is that we have a group of humans that are incentivized to live in an area that isn't safe to live, full stop.

Said with tongue firmly planted in cheek:

"The Himalayas are the highest, youngest, and most unstable mountain system on Earth. Let's terraform these bastards to extract energy and incentivise people to live there. They can build these giant, terribly unsafe, concrete buildings right on the bank of a river fed by a an unstable glacier. Let's also have one way in and one way out! The mountains are too steep for meaningful egress upward, so rock crawl your way out there for the bi-seasonal melt floods!!!!"

Are SF, and LA not built on fault lines? Is Tokyo not built in the middle of them? Is Omaha not right in the middle fo tornado valley? Why do people settle in Florida when it gets hit by tornados. Everywhere has a inherit risk with it, maybe they like it there or are from there. Victim blaming them isnt helpful

That absolute worst combination of factors that could combine in this disaster did indeed combine.

I thought this was going to be an Intel cpu security issue

These Intel chips are getting out of hand

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