You don't need anything elaborate. Just a couple three power bars or "Granola" bars. Some good winter gloves and head cover (I've got one of those wool jobs with the danglies that come down over your ears), a GOOD "Space" blanket at least (Search for all weather blanket, they aren't the flimsy single ply you normally see).

Just think what you would need in your vehicle to keep you from freezing to death if you were stranded out in the cold for a couple days.

I ALWAYS carry two 25oz water bottles in the truck. I'm always drinking out of them, year round. When one is about empty in the house it goes to get refilled and the other one gets utilized.