I read this wasn't due to rain but a glacial collapse. It sounds to me like the additional advice would be that due to a warming climate, avoid being under a glacier at all costs?

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defrost a day ago | parent [-]

Down stream of a glacier, in the run off water shed.

As I've heard tell, this was a glacial collapse into and blocking a river, which then built up a head of pressure behind it, bursting to release a hammer blow of river water and debris that travelled a great distance.

Similar things can happen due to landslides into rivers; it depends on the topology of the land, here long narrow valleys carved out by heavy water flows.

The warning being, don't live in a natural "drainpipe".

In mountainous regions that's often not much of an option, there's a lot of vertical sides and valley bottoms.

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dredmorbius 10 hours ago | parent | next [-]

The specific geological cause is not yet clear.

We do know that a glacier substantially collapsed.

What contributed to the amount of water in the debris flow isn't clear. Speculation, from trained geologists, is that the friction of the glacier flow itself contributed to melt. I'm speculating that recent rains or higher temperatures might have contributed to melting on the glacier (and have seen some commentary speculating about this).

Speculating on my part: There might also have been accumulated water below the glacier, liberated by the ice flow, or perhaps groundwater which was evacuated along with other material. Events seem to have precipitated too quickly (roughly 7 minutes from galcial collapse to Gyirong Port inundation) for the collapse to have formed, then broken, a dam on tributary waterways upstream of the port.

GLOF is a recognised threat, but this event seems to have been at best only partially explained by that, and may be an entirely different mechanism. The follow-on studies should be fascinating, in the way that horrific disasters often are.

	▲	defrost 9 hours ago \| parent [-]
		That all tracks - good additional comment. > Speculation, from trained geologists Probably about on par with speculation from trained geophysicists I'd warrant.

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jltsiren a day ago | parent | prev | next [-]

The rivers in that area are pretty small. You would have to block them for days before there is a risk of a massive flash flood.

From what I've understood, the collapsing glacier either contained enough liquid water or melted enough from the impact that it continued flowing downstream. It covered ~20 horizontal kilometers in about 7 minutes before hitting the border crossing.

	▲	defrost a day ago \| parent [-]
		There's a few ways this could go and very likely no video feed to be sure. It had the look of a large volume of water quickly released. Massive tonnages breaking off of a glacier is still going to be mostly ice on impact .. there's a chance debris and ice chunks made a temporary dam as the bulk of the now shattered glacier ice released water putting pressure on that weak dam - leading to collapse and release.

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bamboozled a day ago | parent | prev [-]

It sounds like there may have been some opportunity for warning then? If the thing was more of a "build up" ?

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defrost a day ago | parent [-]

Sure, if every part of rugged terrain were monitored with sufficient frequency to detect such a change.

That might take some infrastructure to cover everywhere such things can happen (eg: the beds of rivers in Western Australia's Pilbara and Kimberley regions have a high flash flooding risk in the wet season.

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bamboozled a day ago | parent [-]

Sounds like a great application for drone tech.

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defrost a day ago | parent | next [-]

Is it?

What's the land area you'd like seamlessly and continuously monitored by a mobile object with moving parts ... and how is that a better solution than using static solar powered instrumentation?

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mandeepj 10 hours ago | parent | prev [-]

Better suited for satellites

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dredmorbius 9 hours ago | parent [-]

Satellites or ground-based observation.

Geologists have used the latter for many decades. Monitors upslope of at-risk glaciers, solar/battery powered, and communicating by radio (or Internet / satellite links) could be part of this.

See for example the extensive seismic monitoring of California's San Andreas Fault, particularly at Parkfield and through the Carrizo Plain / CA Hwy 25.

<https://earthquake.usgs.gov/learn/parkfield/safod_pbo.php>

<https://en.wikipedia.org/wiki/Carrizo_Plain>

<https://en.wikipedia.org/wiki/California_State_Route_25>

(Different tech, obviously, but in situ ground-based sensors which share some similarities.)

	▲	defrost 9 hours ago \| parent [-]
		Ground based field instrumentation on specific potential threats has the advantages of being up close and always on target whereas sat observation is distant and intermittent. Multiple sat observations a day is great, obviously, but sudden collapses / changes often won't get flagged for seven or eight hours after the event.