This is an interesting piece, with a link to a better, more in depth look at the issue. Two years ago a solar storm erupted and there were two coronal mass ejections, one after another. Fortunately for us they were about a week off on our orbital positions and managed to miss us. If they had hit us, we'd have been FUBAR. The grid would have likely gone down, and could still have been down. Electronics would have been fried and done. It was sheer luck that we got missed, but we may not be so lucky next time and there's just so little you can do to prep for this type of event, (other than having food and water on hand for an extended time). Experts are predicting a 12% chance of a re-occurrence in the next 10 years. This would be a world changer SHTF. (Looking back at threads on CME's from that period, we here at INGO didn't hit on those, but we did on CME's and solar storms just before and after).
How a solar storm two years ago nearly caused a catastrophe on Earth
How a solar storm two years ago nearly caused a catastrophe on Earth