From a New Orleans resident and someone who lived through the whole thing:

FEMA was there only to protect those in authority. The military actually sent armed troops to the city - not to help with rescue efforts (although they did eventually distribute MREs. Kinda like they'll be doing soon in our "fifteen minute cities"), but to watch the COPS who were looting and pillaging for themselves.

PS The Superdome is actually very nice, especially now with over $1.5 billion in improvements. During Katrina it was indeed a shithole. The Convention Center was actually even worse.

and yes, almost all of New Orleans is under sea level. Only the French Quarter and the areas nearest the river levees are above ses level. I guess those colonists 300 years ago weren't so stupid after all. The city should never have been expanded beyond the French Quarter.

And don't forget that the true disaster of Katrina wasn't the hurricane, but instead the levee break. The levee, of course, being built by the Army Core of Engineers and inspected annually (guffaw). Without the flooding, Katrina would have been just another windstorm. Hurricane Ida a couple of years ago gave us what Katrina would have been without the levee break. A few weeks of no power and that's it.