"Communities there just didn't have the jobs, they didn't have the housing, they didn't have the funds to provide schooling and health services," Gregory said. "They were overwhelmed by the introduction of hundreds of thousands of poor people into their communities. And that led to not only real problems for the migrants, and for the communities who couldn't fund this, but also it set up a pattern of long-standing hostility between the newcomers and the older residents."
Though it's hard to grasp that kind of massive possible population shift now, Ted Shaw, the director-counsel of the NAACP Legal Defense Fund, says the government must start planning on how to deal with an influx of hurricane evacuees to various communities across the country.
"Government is going to have to figure out how to respond to this relocation, of jobs, of questions of whether these people are gonna get housing, the question of what their rights are with respect to relocation, whether they come back home, whether they have the right to vote, all of these questions are up for grabs. We're seeing something like we haven't seen in the last 70 years in this country," said Shaw.
Jeff Farrell, a sociologist at the Texas Christian University who has studied urban displacement, says the signs of potential strain aren't hard to find, even this early.
"I think part of it is that we're seeing, for example, here in Texas schools that are barely funded if they're funded at all ... social service networks and criminal justice agencies that are already overburdened," Farrell said. "So obviously when you flush into those systems hundreds of thousands or millions of new people that's going to create even greater strain on those systems."
Gregory adds that communities that have initially welcomed hurricane evacuees may soon change their minds when they realize the financial burden. "And if that happens, we are gonna see the 'welcome mat' withdrawn, and the 'go away' signs go up," he said.
Among the major changes that communities can expect, especially if they absorb large numbers of evacuees, are cultural changes. For example, many of the Okies settled in California's San Joaquin Valley, bringing with them country music and the Protestant evangelical movement rooted in the Bible belt.
"California was transformed by the Dust Bowl migration," said Gregory.
Before analyzing the cultural impact of a mass relocation of evacuees, Ted Shaw of the NAACP says the question is: Do these people want to go home and how can we help them rebuild?
"I'm not willing to talk about a cultural impact on other cities because that sounds like these individuals will not go home," said Shaw. "And I think in the first instance we ought to be trying to get these people back home. And we ought to be talking about rebuilding New Orleans and addressing the questions of poverty."
Farrell agrees, saying that if nothing else, the hurricane has brought to light the often overlooked inequities in American society.
"Not only has this created problems, it perhaps has shown us some problems that we were ignoring," he said. "I think we have to look at liveable wages and viable jobs and rebuilding communities in ways that provide social supports for all of their members. And that's not an overnight process."
Those who do relocate will have to learn to adapt to their new homes. We can look back at how history played out for the Okies in California.
"Well, people made new lives for themselves," Gregory said. "Some went back. But most stayed in their new homes, and became Californians, and learned to love California and, and fit in, and build new lives, and livelihoods.
"So in a certain, very long-term sense, most Dust Bowl migrants felt that they had lived through a successful experience. And hopefully, the Katrina people will feel the same, in time. But it's gonna take time. This isn't a short-term process, at all."