Really? I did not know that. Thanks for the info! I had presumed on the basis of that mentally unstable sherriff that was on the TV shows after Katrina that St. Bernard leaned Dem. If it is instead staunch conservative, to me that definitely suggests Katrina improved the electorate for Melancon.
Note that I was careful in my wording above not to indicate which direction the doubt may go in LA-03, because in my thinking it could go either way. It had occurred to me that suburbs, especially in the South, tend to be firmly GOP, and that the parts of LA-03 that seemed as if they would be affected by Katrina were suburban, and so that if anything a population shift seemed more likely to help than hurt Melancon.
For the time-being, I will continue to rate LA-03 as if Katrina didn't happen.