"choppers moving into evac from those overpasses now. I'm confused why they need helicopter rescues there, it is accessible by road"
Maybe all the rolling stock is tied up moving the Convention Center crowd out From what I understand, they diverted (cynically - due to Geraldo's hystrionics) all available transport to that task, leaving, at last report, some 2000 people stranded at the Superdome.
yes, but those 2000 people at the superdome are new arrivals there,not part of the original set. the convention center needed the evac for sure.