Due to the massive flooding, with rescues continuing along with power outages and communications problems, it's too early to know how many people died and how many lost their homes.
Mississippi late Monday night announced the grim news that at least 55 people were killed - 50 of them in Harrison County, most in an apartment building in Biloxi. At least three were killed by falling trees as Katrina meted out what Mississippi Gov. Haley Barbour called "a grievous blow" to the Gulf Coast state.
Barbour said people who evacuated from south Mississippi and Louisiana should not travel home until officials give the all-clear - possibly in several days. He also strongly warned against looting in storm-ravaged areas.
"To me looting is about the equivalent of grave robbing," Barbour said. "We're not going to stand for it."
In Alabama, at least two people died in a highway accident related to the storm.
Katrina's danger remains: Tennessee and Ohio could get eight or more inches of rain. The storm system is also ideal for spawning tornadoes, which so far have damaged at least 30 homes in Georgia.
Hurricane Katrina plowed into the Gulf Coast at daybreak Monday with shrieking, 145-mph winds and blinding rain, submerging entire neighborhoods up to the rooflines in New Orleans, hurling boats onto land and sending water pouring into Mississippi's strip of beachfront casinos.
In addition to known deaths, and an untold number of others were feared dead in flooded neighborhoods.
"Some of them, it was their last night on earth," Terry Ebbert, chief of homeland security for New Orleans, said of people who ignored evacuation orders. "That's a hard way to learn a lesson."
Katrina weakened overnight to a Category 4 storm and made a slight turn to the right before coming ashore at 6:10 a.m. CDT near the Louisiana bayou town of Buras. The storm passed just to the east of New Orleans as it moved inland, sparing this vulnerable below-sea-level city its full fury and the apocalyptic damage that forecasters had feared.
But there was plenty of destruction in New Orleans, and a clearer picture of the damage emerged after the storm had passed: Mangled street signs, crumbled brick walls in the French Quarter, fallen trees on streetcar tracks, highrises with almost all of their windows blown out. White curtains that were sucked out of the shattered windows of a hotel became tangled in treetops.
An estimated 40,000 homes flooded in St. Bernard Parish just east of New Orleans.
But as CBS News Correspondent John Roberts reports it was bad, but city officials had expected much worse. Only a last minute jog to the east saved New Orleans from catastrophe. A city that has become famous for near misses took a hard punch, but not the knock-down it could have been.
Elsewhere, Katrina recorded a storm surge of more than 20 feet in Mississippi, where windows of a major hospital were blown out and billboards were ripped to shreds. In some areas, authorities pulled stranded homeowners from roofs or rescued them from attics.
"Let me tell you something folks: I've been out there. It's complete devastation," said Gulfport, Miss., Fire Chief Pat Sullivan.
CBS News Radio reports that Federal Emergency Management Agency director Michael Brown urges those in the path of the storm to be patient and not venture out.
In Alabama, exploding transformers lit up the early morning sky and muddy, 6-foot waves engulfed stately, million-dollar homes along Mobile Bay's normally tranquil waterfront.
Alabama authorities today closed a major bridge over the Mobile River after it was struck by a runaway oil drilling platform during the storm. Officials said the bridge on U.S. 98 will remained closed until it can be inspected for damage.