Prime
When power is out the first thing I do is to add a full dose of Prime to the tank to contain any ammonia. At my 8.0 pH any ammonia is a bad thing.
In the overstocked discus tank, 16 big fish in 105 gallons, I have a battery operated airpump tht comes on automatically that keeps the sponge filter in there running. the HOB filters I wouldn't worry about until several hours had passed.
In the other discus tank I have canisters which are more of a concern but that tank has live plants so if I can open the shades to get sunlight on them, they will do OK, pretty much.
Now, in the case of a hurricane, I'd store a lot of water in a barrel for fish water, clean the filters well before the storm arrives, reduce feeding. When the power is out, I'd uncover tops and net the tanks, run the battery airstone/sponge filter, add Prime, don't feed at all. After the storm is done, the first water change can be dangerous if floodwaters mixed with watermains, and the water company may add nasty chems to the lines and not tell you. Be cautious with changes, smallest, least important fish first!