[Blood of Tyrants]

A high altitude nuclear burst over central US wold take out 70% of the grid. Another over DC and one over central California would take out the rest. 80-90% of the population would die within 4 months.

[Steely Tom]

Yes, but this article is talking about induced currents from the interaction of a CME with Earth's magnetic field.

The rise time of such an event would be thousands of times longer than the rise time of an EMP impulse. Long enough for protective gear to operate.

And EMP pulse would be a different matter.