Originally Posted by
RatherBeFlying
RF incompetence is a strong competitor to deliberate destruction.
It seems spillway control had been inop since November. Once water overtops an earthen barrier, the collapse is usually pretty quick. There's lots of YTs showing dam collapses.
The evidence I've looked at suggests you're right. The water level had been a metre and half above the max for a while. Once water gets under the concrete it most likely just washes the foundation away.
What's not clear is why the initial failure happened. Could be just a failure because Russia hasn't managed the dam. The timing suggests it was deliberate though. The missing road section over the top of the flood sluice gate also hints at it being deliberate. Russia reportedly laid demolition charges in that area last year. A charge going off on or over the flood sluice gate during the night of 1st/2nd June may have been what blew than road section away.