The February 8.8 quake in Chile unleashed a torrent of looting and criminal behavior. The linked video shows a TVN 24 hour News story on the chaos that followed. Some residents banded together, with and without firearms to defend themselves.
It's an enlightening view of the aftermath of a large disaster and how people react to it. I think it's worth watching several times to understand what you'll need to organize.
Chilean Quake AftermathNotice that looters didn't confine their activities to just stores and businesses. They went after apartments and even people living in makeshift shantys.