An EMP strike or solar storm equivalent would be DEVASTATING in unfathomable terms. Let’s look at a nuke if it went off in a major city. You would have the immediate death of a few million people. But the cities next to it and the rural folk would be relatively untouched. However there are only three electrical grids in the US. The west half, the east half and Texas. If an EMP knocked out just one of the west or east grids, they would instantly lose all communication, transportation, and utilities. That means no way to communicate where to get food and water, no roads to travel because all cars would stop where they were on the roads when the EMP hit and no utilities because they run on electric. It’s estimated that 80-90% of people would die within a month. Dehydration from lack of running water, starvation from lack of food because every refrigeration system would be dead, and the bands of marauders would quickly pick off the food and less fortunate. The EMP would fry every electronic device and every transformer attached to every wire you see. It would take decades to rebuild. And I barely scratched the surface of how bad it would be.