I think Am Fear and Nighthiker did a good job of explaining the base dynamic behind a riot.

With a natural disaster, organized or (more likely) opportunistic looting is what you are going to get. The only time I've witnessed looting in the US first hand was during an ice storm. Some areas were without power for over a month. We were lucky and only lost power for 4 days. We saw a few cars cruising areas without power looking for easy pickings. It didn't take much effort on our part to appear to present more of a challenge than they were willing to deal with.

From 1500 miles away it's hard to know what the situation on the ground really is in the areas affected by Sandy. I pray that for the most part, people are banding together and taking care of each other. They still have a rough bit in front of them.