"If you draw on the stress literature, the kind of constant on-the-alert mentality created by the threat of repeated evacuations keeps your physiological stress system activated," says Martha Wadsworth, professor of psychology at the University of Denver who studies the impact of disasters like Katrina. "The folks who are able to be the most resilient through this are people who have lots of good resources, whether it's a well-connected religious community or more financial resources."
With hurricane Gustav downgraded Tuesday morning to a tropical depression, one of the largest evacuations in America's history has been pronounced on the whole a success – especially when compared with the chaos surrounding hurricane Katrina three years ago.
Many of the almost 2 million Gulf Coast residents who jammed Louisiana and Mississippi highways over the weekend in caravans of crowded cars and overloaded buses are ready to turn around and head home.
New Orleans Mayor Ray Nagin says they could be welcomed back in the "Big Easy" late Wednesday or Thursday, despite the looming storm threat of Hanna, which is now brewing over the Bahamas, and Ike, which is speeding west over the Atlantic.
When the order came down to get out of the way of what was billed as "the mother of all storms," more than 95 percent of people on the Gulf Coast heeded the call.
"People now have it down. They have their bags packed, their photo albums and their documents ready, but the toll [evacuations take] is still enormous," says Alice Fothergill, a sociologist who specializes in displacements and evacuations at the University of Vermont in Burlington.