The good news is that this may, repeat may, have been a rather benign surge event, a slow rise rather than a tidal wave... Yes, indications seem to be that the rise was gentle, and not like what happened in Mississippi. I guess it's the difference between Cat 3 and Cat 4.
i think that flooding being caused isn't a true storm surge..yes there was a surge too but now the wind in still onshore slowing down the flow back to the gulf. meanwhile all the rain that fell is draining out but getting backed up..
in other words more water is flowing into the gulf now then is moving backout..creating a backup...that would explain the "slow" water rise and why it is still rising in places