New Orleans resident Richard Thomas heard the orders to evacuate ahead of Hurricane Katrina. But like thousands of others, he chose to stay and ride it out.

"They wanted to move, they wanted to go to Mississippi, but I said I wasn't going to go," he said.

"But I should have went, because we got a lot of water here. A lot of water."

When calm returns to an area devastated by a natural disaster like Katrina, it is hard for many people to understand the mindset of the people who ignored evacuation orders.

Why didn't they just get out of town?

"There's a certain amount of denial involved," said Dr. John Stutesman, director of outpatient treatment in psychiatry at Chicago's Northwestern Memorial Hospital. "They allow themselves to believe they can handle the storm."