You may have seen recently in the news stories about a coronal mass ejection (CME) that narrowly missed the Earth in 2012. It apparently was at least as big as the CME which caused the Carrington Event in 1859, the largest CME on record, and twice as strong as the CME that caused massive power outages in Quebec in 1989.
NASA has also provided a nice video explaining the storm:
According to the NASA article, there’s a 12% chance that we could experience another bit hit in the next decade. (Or if you prefer a more optimistic view, there’s an 88% chance it won’t happen.)
If we’d been hit by the 2012 Solar Storm, the damage would have been far more severe than some fires started at telegraph stations. It’s likely that extensive sections of the power grid would have been brought down and we’d still be recovering from the hit. This would be a true TEOTWAWKI event. Unfortunately, this is the kind of thing that’s really difficult to prep for, unless you’re Amish.