Barrier lake continues to pose flood risk, China warns(kathmandupost.com)

47 pointsby r7213 hours ago2 comments

japhyran hour ago
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-...
- monkmartinez20 minutes ago
  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.
lightedman2 hours ago
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.
- Flaviusan hour ago
  > 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.
  - applfanboysbgon33 minutes ago
    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.
    monkmartinez6 minutes ago
    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!!!!"
  - glitchcraban hour ago
    Quite, it's the volume water and the speed of release which matter, nothing else.
    lightedmana minute ago
    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."
  - 0xd00d0031 minutes ago
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