In New Orleans, there was significant damage but also sighs of relief that the city had escaped the utter devastation predicted if the levee system had failed and unleashed catastrophic flooding.

"It's not life-threatening," said Josephine Elow, 73, as she tried to hold together a set of broken doors at the hotel Le Richelieu. "God's got our back."

Calling it a once-in-a-lifetime threat, New Orleans Mayor Ray Nagin had ordered a mandatory evacuation Sunday for residents of the vulnerable city, and he estimated that 80% heeded the call.

Some didn't, however, possibly leading to deadly consequences. "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."

There were widespread reports of serious flooding. The Associated Press reported that near Lake Pontchartrain, entire neighborhoods of one-story homes were flooded up to the rooflines. Up to 20 feet of water was standing in one neighborhood on New Orleans' east side.

On Jackson Square in the historic French Quarter, two massive oak trees outside the 278-year-old St. Louis Cathedral came out by the roots, ripping out a 30-foot-section of iron fence and shattering the thumb and forefinger of the outstretched hand of a marble statue of Jesus Christ.

In downtown, Katrina shattered scores of windows in high-rise office buildings and on five floors of Charity Hospital, forcing patients to be moved to lower levels.

But there was also a sense that New Orleans, where residents have been blessed with good fortune in never suffering the storm that could destroy their below-sea-level city, had dodged a bullet.

Louisiana Gov. Kathleen Blanco wasn't so sure. "I can't say that I feel that sense that we've escaped the worst," she said. "I think we don't know what the worst is right now."

At Ochsner Clinic Foundation, a hospital in New Orleans, press officer Aimee Goforth said the only saving grace of a scene she described as frightening was that the storm came during the day and patients knew what was happening.

The hospital was running on emergency generators, but the air conditioning was off. "One of the nurses said there's nothing worse than being sick and in a Category 5 hurricane," Goforth said. Katrina was a Category 5 storm Sunday but weakened slightly to a Category 4 shortly before landfall, and later fell to a Category 1.