The article says that the typical CME takes several days to reach earth, and the superstorm observed in 1859 took 17.6 hours. In either event, there would be at least some warning time. Question: if electronic equipment was turned off, would it be ok? If so, that would be an interesting scenario: a big solar storm is coming, and the challenge would be to power down as much as possible to ride it out.
“Question: if electronic equipment was turned off, would it be ok?”
In a solar storm electronic equipment will not be impacted by the storm itself. So your equipment can be on, or it can be off, plugged in, not plugged in, it makes no difference.
The power may go out, but that is it.