I wonder how similar Katrina is to the 1900 Galveston hurricane. Galveston was almost, if not entirely, underwater after the storm passed. New Orleans may be underwater for weeks as the water inland keeps flowing south through the Mississippi.
It's hard to compare the 1900 storm, but if this Katrina hits NO, the property damage is sure to be much worse, and I can only pray the death toll will be less. Galveston in 1900 lost a lot of lives---many thousands---because so many people didn't take the warnings seriously, and many heard no warnings at all. Plus there was a Labor Day surplus of vacationers.
Galveston Island was no more than 15 feet above sea level at its highest point, and yet with high tide and storm surge, it was probably fully submerged around late afternoon. The physical damage from the storm was largely due to debris pounding against buildings in successive waves, street by street in some places, the houses fell like dominoes and were sent to the next row to batter more houses down. Flying debris was everywhere---which is why I can only shudder at the idea of packing people into a superdome for shelter. Winds at the superdome, surrounded by tall buildings, would be higher than winds at ground level, and they would be delivering deadly missiles of debris.
Another point of non-comparison: in Galveston, 1900, there were no offshore oil rigs, no chemical spills to worry about. The worst thing in the water afterwards was carrion, and Nature cleaned up after herself.
I think the superdome is about 270ft. high. Built in the '70s. Hope they planned ahead.