You can see my extended explanation above, but in short it was due to a glacial moraine outburst flood upstream, releasing two-thirds of the water of Lhonak Lake in one go. The lake was known to be at high risk of bursting the moraine.
The lake itself was caused by glacial melt due to global warming, first appearing in the 1960s. The bursting of the lake this summer will almost certainly be traced to the record high temperatures recorded this summer, which led to an increase in size of the lake and overtopping the moraine that held it in place.
This article has satellite images showing the recent growth of the lake and then the recent release of most of its waters:
And, why did they not have some kind of early warning system set up to give them more notice of the breaching of the Lhokan Lake moraine? The moraine was known to be in imminent danger of breaching.
https://www.sciencedirect.com/science/article/pii/S0169555X21001914
The way this (completely predictable and preventable) man-made disaster is being covered is both ridiculous and infuriating.
Every news outlet is dutifully reporting that a “cloudburst” over Lhonak Lake led to a “flash flood” which then (somehow?!) took out a 25,000 crore ($3 billion) dam in a brief 10 minutes.
So here is a “cloudburst” and a “flash flood”: https://youtu.be/FJOpZF_4b-w?si=fqZ31FGJVy5xx5JT&t=463
What happened in Sikkim is emphatically NOT a simple little cloudburst nor a simple flash flood.
What is really was: A huge glacial-moraine dammed lake that first appeared in 1962 and that has massively grown in size the past few years - all due to global warming - finally breached the moraine. About 2/3 of the water of the lake poured through the breach in a short while.
Pro tip: That is not a “flash flood”. That is a glacial lake outburst flood - which, given the size of the lake, is several orders of magnitude larger than a simple flash flood caused by a thunderstorm.
This massive bolus of water then struck the massive, $3 billion Teesta 3 dam at Chungthang, 60 meters high and just recently completed, washing it away in 10 minutes flat and causing an even LARGER flood due to the dam breech and loss of the entire, massive reservoir. This released an additional 5.08 million cubic meters of water to wreak havoc downstream.
So a few points:
In short: Don’t blame the cloudburst. This was an entirely human created, human caused, disaster that could have been averted, or at least greatly minimized, with by relatively simple means and a little bit of foresight.
Not all news outlets are blaming the disaster on a “cloudburst”:
So why is every mainstream news outlet in India erroneously referring to the disaster as a “flash flood” caused by a “cloudburst”? It took me literally 2 minutes of googling to find out the actual cause.
My last couple of phones have definitely had it (Motorola).
I haven’t read it myself but by pure luck I happened to read a piece by Henry Farrell today that had his take on the book:
Not having read the book myself, I can’t say if I agree with that or disagree. But there it is, for your consideration!