During our last extended (3 day) power outage, I was surprised to learn that even though I have all of my gear on a very large UPS, the cable network also ceases to function after a few hours. Local nodes apparently only have backup power for a short time. To their credit, I saw Comcast deploying small gas generators to nearby street poles the next day.

The cell network, on the other hand, continued working without a hiccup. This might have been because the nearest cell tower still had power, but even if it didn't, I'd assume that I'd just be able to connect to the nearest in-range tower that _did_ have power.