Don’t freak out! We have a lot of power outages in Houston during hurricane season

. A lot of the above info is really really good. Every 1-2 hours stir the tank with a wooden spoon to keep everything moving and do the pouring water thing mentioned earlier. Run out to a bass pro shop/ academy (or similar) and get a battery powered air pump plus batteries, pop that sucker in and even the coral should be okay for at least 3 days.
I went to Florida and kept 20 zoanthid polyps plus fish and inverts I collected alive for a week in a styrofoam cooler with just a battery powered air pump.
I see you’re in Oregon, I assume temperature is a concern since it’s February and you’re without power. If you have any quilts/comforters wrap the tank immediately and put a solid lid on. So if you have a mesh lid right now, cover it with a blanket or cardboard or something like that. Keeping heat in is very very important for long-term power outages. You want to try to keep it between 70-79 degrees. If you can run out and get fire wood, build a fire outside and start heating water for keeping the tank warm (and make some s’mores while you’re at it!). Get some hot hands (oxygen activated heat packs) if you can, Walgreens/CVS carries them and I think Walmart does as well. Thin sheet over the entire tank, heat packs, then thicker comforter over that. Remember hot water rises so try to place the heat packs towards the middle/bottom.
Doing all of that, you should be good for a couple hours at least. Overnight would be very difficult if you can’t get a battery air pump since you’ll have to manually re-oxygenate the water every couple hours. Best of luck, I hope all your fishies are okay and that a lot of your coral makes it as well!