I believe the "Carrington event" relates to a solar storm that would knock out most electronic means of communication. How is the current banking system protected from the same event? If anything Bitcoin is more resilient as the blockchain (public ledger) is replicated across 1000s of PCs.
Indeed, it is. No matter the length of delay, the bitcoin network can pick up right where it left off once the Internet was back up, regardless of whether or not the outage was a local, national or worldwide event. BTW, the Carrington Event wasn't worldwide, and another similar solar flare event would also be unlikely to be worldwide. The hardest hit area would be the side of the Earth that leads into the flare, and high latitudes are better defended by nature of the field density of the Earth's magnetic field, so there would be variations in the extent of damage. Some banks might have their records competely destroyed, others hardly effected. Bitcoin would be safe
somewhere.
A bigger issue with a Carrington type event would, sadly, be clean drinking water. 90%+ of the population of the United States is dependent upon regular electric service to maintain the municipal water utilities, since most don't have water storage that exceeds three days of regular demand.