SHORT NOTICE: New Orleans Mayor Ray Nagin didn't issue a mandatory evacuation order until the day before the storm.
PEOPLE WOULDN'T LEAVE: Tens of thousands along the Gulf Coast ignored evacuation orders, deciding instead to ride out the storm in their homes.
PEOPLE COULDN'T LEAVE: Survivors trapped in New Orleans after the storm waited days in the convention center and the Superdome for a ride out of the city as babies went without milk and the frail died.
INSUFFICIENT SHELTERS: Some 25,000 swarmed into the Superdome and thousands more went to the convention center. Both became disaster areas in themselves, overrun with people and lacking basic necessities that were not in place before the storm.
POOR COORDINATION: Even now, hundreds of firefighters are waiting in Atlanta for directions on where to go to help, and other emergency workers have aired similar complaints.
NO BACKUP COMMUNICATION: New Orleans police complained they could not contact their headquarters after Katrina hit, while reporters were contacting their home offices by handheld satellite phones.
INADEQUATE SECURITY: Looting was widespread in New Orleans, Gulfport and Biloxi, Miss., before the National Guard and others established order.
POOR PLANNING: The levees of New Orleans were known to be vulnerable, and had been the subject of extensive reports in the local Times-Picayune and even National Geographic.