[roadcat]

Next would be a headwaters dam, which would start a domino effect, taking out other dams downriver.

Beat me to it. All they need to do is take out lesser dams upstream to begin the domino effect to take out Three Gorges Dam.

[yefragetuwrabrumuy]

It happened in Soviet Georgia, resulting in 5 dam collapses. It had no warnings, and they reported a laughably small number of casualties, which was par for the course in Soviet era disasters.

Or as someone observed at the time, “Russia has no disasters but the very worst.”