If its the Gulf Coast primarily from which the come, for the most part we are talking about Republicans.
Keep in mind there will also be a wealth skew in terms of those able to move.
That can go both ways, though, because impoverished people have the most incentive to leave. It was generally the poorest people who fled the Plains states during the Dust Bowl.
Also the case for Katrina migrants, who
had to leave, and IIRC the city was repopulated in large part by gentrifiers especially post-Great Recession. With ideas like the Green New Deal and mutual aid floating around, we could also see a lot of idealistic young environmentalists and social workers flocking to devastated areas to help with reconstruction.