I live somewhere with two nines of utility power reliability, I mention that to say everybody's backup (or lack thereof) is well tested. I've got UPSes on most of my computers and a standby generator that pops on after about 10 seconds. DSL from my ILEC has zero backup power; sync drops when the power drops. I don't know about the cable. Municipal fiber doesn't drop so far, but I haven't had a long outage since I got it; my ISP has a generator where they route customer packets. We get cell coverage for about 4-8 hours, depending on which network you're on and if the outage started overnight coverage usually lasts until people wake up.

After that, communicating with the outside world is hard for most people. Time to make babies ... anyway it's often cold, so snuggling is likely.