I have photographs the aftermath of natural disasters such as floodings and an earthquake in the rural parts of Japan. It's not that I want to be a photojournalist of some kind concerning these tragic events, but it's just that I'm more aware of the environment that I live in, and I feel like I need to do something about it.
My best approach to photograph those scenes has always been that I become a volunteer worker and serve for a couple of weeks. That's just a way to be part of the communities that need outside help and create a sense of trust among the survivors/victims as well as the local authorities.
For the survivors/victims of the disasters, the last thing they need is someone who is just hanging out with a camera and staying all clean. They need a lot of help with a lot of privacy, and that's really the job that needs to be handled carefully. So you really need a strong belief and a reason to convince them that what you're doing is important and is unarguably beneficial to them.
I don't think in the case of hurricane katrina, the issues that were concerned during the aid operations are that different from what I've seen over here.