The dam is in no danger. The spillways are the problem. The main spillway is badly damaged, and the emergency spillway was in some danger of collapse on Sunday.
The main spillway is a long straight concrete chute with a gate at the top to regulate the flow. If the erosion in this spillway worked its way up to the top, it could damage that gate and operators would lose the ability to control the outflow.
The emergency spillway is a low concrete wall with a hillside below it. Its top is lower than the dam top, so water will go over this wall (and did on Sunday) instead overtopping the dam itself. The worry here is that erosion of this hillside could cause the wall to collapse.
Both spillways are separated from the dam by a large hill. Even if they failed, the dam would survive. So there wouldn't be a flood of all 700 vertical feet of the reservoir, but there could be a flood of 30 feet from the emergency spillway.
Of course if you were in the path of that flood, the distinction between the "dam" and the "spillway" would be small consolation.
The Metabunk page that seanp2k2 linked has some good information and discussion:
No. At least not strictly speaking.
The dam is in no danger. The spillways are the problem. The main spillway is badly damaged, and the emergency spillway was in some danger of collapse on Sunday.
The main spillway is a long straight concrete chute with a gate at the top to regulate the flow. If the erosion in this spillway worked its way up to the top, it could damage that gate and operators would lose the ability to control the outflow.
The emergency spillway is a low concrete wall with a hillside below it. Its top is lower than the dam top, so water will go over this wall (and did on Sunday) instead overtopping the dam itself. The worry here is that erosion of this hillside could cause the wall to collapse.
Both spillways are separated from the dam by a large hill. Even if they failed, the dam would survive. So there wouldn't be a flood of all 700 vertical feet of the reservoir, but there could be a flood of 30 feet from the emergency spillway.
Of course if you were in the path of that flood, the distinction between the "dam" and the "spillway" would be small consolation.
The Metabunk page that seanp2k2 linked has some good information and discussion:
https://www.metabunk.org/oroville-dam-spillway-failure.t8381...
And the YouTube video that clamprecht linked has a good view of the dam and spillways on Sunday:
https://www.youtube.com/watch?v=q2YHGR3kVLk&t=2m24s