Have you got a large cooler? You could use that for short term and if you have to get out it will make it easier to move them. For heat you might want to think about a car battery and a headlight [car, tractor, ATV, doesn't matter.]. Jump wires from the battery to the prongs of the headlight and a cake cooling rack over the top of where they are. I am not sure how big an area the birds will be in so watch the temp.. Headlights get quite warm. Aluminum foil will work to line the walls of a box and the cover. Something else I just thought of. Most auto supply stores sell a small heater to defrost windshields. They're about $20 and work from a car battery. You might have time to check into that. Hand warmers, the battery operated ones or the packs you can get at Walmart. You didn't say how many chicks you have so I don't have a good idea on how large a space you will need to warm.With the storm coming up on the East Coast, I'm really worried that our power will go out, leaving my 4-5 day old babies without a heat lamp. I've seen people recommend hot water in bottles and bricks, but is there any other advice I should know about?
Your biggest problem is going to be water and food for yourselves and them. Pack their food into something waterproof so if you have to run it'll stay dry.