The mayor ordered an immediate evacuation Sunday for all of New Orleans (search), a city sitting below sea level with 485,000 inhabitants, as Hurricane Katrina (search) bore down with wind revving up to nearly 175 mph and threats of a massive storm surge.
Acknowledging that large numbers of people, many of them stranded tourists, would be unable to leave before the eye of the storm strikes land sometime Monday morning, the city set up 10 places of last resort including the Superdome (search).
"This is a once in a lifetime event," Mayor Ray Nagin (search) said. "The city of New Orleans has never seen a hurricane of this magnitude hit it directly."
The mayor said a direct hit by Katrina's storm surge would likely top the levees that protect the city from the surrounding water of Lake Pontchartrain (search), the Mississippi River (search) and marshes. The bowl-shaped city must pump water out even during normal times, and the hurricane threatened electricity that runs the pumps.
Nagin said he spoke to a forecaster at the hurricane center who told him that "this is the storm New Orleans has feared these many years."
President Bush pledged federal support.
Rain started falling on extreme southeastern Louisiana by midday Sunday as the storm moved across the Gulf of Mexico toward land. Highways in Mississippi and Louisiana were jammed as people headed away from Katrina's expected landfall. All lanes were limited to northbound traffic on Interstates 55 and 59 in the two states.
Beyond the Gulf Coast, Katrina was "unmitigated bad news for consumers" because it had shut down offshore production of at least 1 million barrels of oil daily and threatened refinery and import operations around New Orleans, said Peter Beutel, an oil analyst in New Canaan, Conn. He said crude oil could top $70 a barrel by Monday or Tuesday.
If Katrina maintained its strength, it would be only the fourth Category 5 hurricane on record to strike the United States.
"I'm really scared. I've been through hurricanes, but this one scares me," Linda Young, 38, said as she filled her gas tank at one New Orleans station. "I think everybody needs to get out."
"Have God on your side, definitely have God on your side. ... It's very frightening," said Nancy Noble, sitting in snail's-pace traffic on Interstate 10 heading for Natchez, Miss. She and three others were packed in a car with a puppy and their essential papers.
The Superdome was already taking in people with special problems Sunday morning. People on walkers, some with oxygen tanks, began checking in when it opened about 8 a.m.
At 11 a.m. EDT, the National Hurricane Center said Katrina's maximum sustained wind speed had stepped up to nearly 175 mph, with higher gusts. The hurricane's eye was about 225 miles south-southeast of the mouth of Mississippi River.
The storm was moving west-northwest at nearly 12 mph and was expected to turn north-northwest. Forecasters said the weather would start getting rough late Sunday and the eye would strike land early Monday but they could when.
The mayor said people who opted to go to the Superdome should take enough food and supplies to last three to five days. He said police and firefighters would fan out throughout the city telling residents to get out and that police would have the authority to commandeer any vehicle or building that could be used for evacuation or shelter.
Hotels were exempted from the evacuation order because airlines had canceled all flights out.
Tina and Bryan Steven of Forest Lake, Minn., sat glumly on a sidewalk Sunday morning outside their hotel in the French Quarter.
"We're choosing the best of two evils," Bryan Steven said. "It's either be stuck in the hotel or stuck on the road."
Robyn Menzel arrived in the Jackson, Miss., area about 8 a.m. Sunday with a two-car group from New Orleans, a trip of about 150 miles she said took an hour longer than usual.
"They were broadcasting that this was serious and they needed everybody to leave now," said Menzel, "We left about 4:40 a.m. and it was pretty bad just getting out of New Orleans."
A hurricane warning was in effect for the north-central Gulf Coast from Morgan City, La., to the Alabama-Florida line, meaning hurricane conditions were expected within 24 hours, the hurricane center said. Tropical storm warnings extended east to Indian Pass, Fla., and west to Cameron, La., a spread of about 480 miles.
"Katrina is comparable in intensity to Hurricane Camille of 1969 ... only larger," specialist Richard Pasch said at the hurricane center. "Hurricanes rarely sustain such extreme winds for much time. However, we see no obvious large-scale effects to cause a substantial weakening the system, and it is expected that the hurricane will be of Category 4 or 5 intensity when it reaches the coast."
Storm surges of up to 28 feet topped by waves up to 30 feet were possible in some areas, hurricane center meteorologist Chris Sisko said. Camille has the record for storm surges at 24 feet.
As much as 15 inches of rain also was possible.
Only three Category 5 hurricanes — the highest on the Saffir-Simpson scale — have hit the United States since record-keeping began. The last was 1992's Hurricane Andrew, which leveled parts of South Florida, killed 43 people and caused $31 billion in damage. The others were the 1935 Labor Day hurricane that hit the Florida Keys and killed 600 people and Hurricane Camille, which devastated the Mississippi coast in 1969, killing 256.
Katrina's landfall could still come in Mississippi and affect Alabama and Florida, but it looked likely to come ashore Monday morning on the southeastern Louisiana coast, said Ed Rappaport, deputy director of the hurricane center in Miami. That put New Orleans squarely in the crosshairs.
"If it came ashore with the intensity it has now and went to the New Orleans area, it would be the strongest we've had in recorded history there," Rappaport said in a telephone interview Sunday morning. "We're hoping of course there'll be a slight tapering off at least of the winds, but we can't plan on that. So whichever area gets hit, this is going to be a once in a lifetime event for them."
Mandatory evacuations were ordered all along the Mississippi coast, where casinos were closed Sunday. National Guard units had already been deployed, state officials said.
Residents of several barrier islands in the western Florida Panhandle also were urged to evacuate Sunday.
"The water is already up to the back of homes on Pensacola Beach and Perdido Key," said Escambia County, Fla., spokeswoman Sonya Smith.
Katrina had been blamed for nine deaths in South Florida. It was the sixth hurricane to hit Florida in just over a year.
Some Alabama coastal residents also headed inland Sunday morning.
"It's scary," said Joyce Allen, a building inspector at Alabama's coastal Dauphin Island. She covered office computers at town hall and left the barrier island, which she said already had some flooding.