I had the same thought. The only thing I could come up with is that it wasn't a failure of power supply, but that a surge took down enough cooling systems that

I had the same thought. The only thing I could come up with is that it wasn't a failure of power supply, but that a surge took down enough cooling systems that they couldn't maintain temperature. A lot of DC's I've seen are N+1 with cooling (or even 2N), but they all run at the same time and are the same units. Or the control system went down, and they weren't able to get it back up and running, although I would think they would have redundancy in that case.