I feel for you all, I used to live outside of KC and don't miss the weather at all. As for your question, keep the water moving! Run a slow siphon into a bucket at one end and gently pour the siphoned water back in at the other. This provides oxygen and water movement. With only LR, I do not believe you have to be as agressive as with inverts and fish, but you need to keep the water well oxygenated and moving. If the power stays out for an extended period, you will also have to worry about the temp. falling. I am not sure how to keep the temp up without power. You could look into renting a small generator, but by the time the power is out, usually the rental places are out of generators. Sorta dammed if you don't and if you do.
Living in the midwest, and wanting to keep a reef, I would definatly invest in a generator! I live in S. Texas and will be getting one for hurricane season, just to be safe.
HTH,
cyn