Twitter says it's below the emergency spillway level now anyways so that damage shoukd not matter from what i understand.
I think gp was getting to the fact that the main spillway is eroding as well, and it could reach a point where it was unusable. In that case, with significant rainfall expected in the next week and a good deal of snow melt to follow, there could be huge amount of water coming into the basin with no way to control the outflow, which could result in much worse flooding.
Hopefully that all can still be avoided. It's a bit dramatic to say it's inevitable. It's a possible scenario, but it's also possible the right plan avoids it.
The thing is... They drained below the emergency spill way level many hours ago and it's off, but they're still running the heavily damaged main spillway at full tilt. I think it's a last ditch attempt to drain the lake before the dam fails, they just don't want to say it because everyone will panic
They shut the main spillway off because of damage and now they're running it at maximum flow because the emergency spillway is even more damaged. This feels every bit like a hail Mary pass to drain the lake as much as possible before the dam breaks. In another day or two they won't have any spillway left.
This dam is doomed, it seems like one of the rare times media is downplaying the risk... Probably because a lot of people are going to die :(