'Recovery will take years'

BATON ROUGE, La. -- The grim enormity of the devastation inflicted by Hurricane Katrina became apparent yesterday in battered, reeling New Orleans, where Mayor C. Ray Nagin estimated that thousands of lives had been lost. State officials announced plans to bus 23,000 residents from the Superdome to temporary shelter in the Astrodome in Houston.

''We know there is a significant number of dead bodies in the water" and others dead in attics, Nagin said. ''Minimum, hundreds. Most likely, thousands."

As National Guard and police patrolled flooded streets, looters ransacked stores throughout the city, carrying away enormous quantities of food, clothing, appliances, and guns. Last night, the mayor ordered 1,500 police to leave their search-and-rescue missions to stop the looting.

Meanwhile, the water appeared to have stopped rising in the city, and the Army Corps of Engineers struggled to repair a damaged levee. Gushing water from Lake Pontchartrain has covered more than 80 percent of New Orleans.

President Bush flew over the disaster area in Air Force One, and he later spoke on live television. ''We are dealing with one of the worst natural disasters in our nation's history," said Bush, who pledged to send personnel, supplies, and money to aid the relief effort.

Bush described a Mississippi Gulf Coast that had been completely destroyed, and said tens of thousands of homes and businesses were beyond repair along the flooded streets of New Orleans. ''This recovery will take years," he said.

Earlier, federal officials declared a public health emergency for the entire Gulf Coast, and rushed food, medicine, and water to the victims, in one of the largest relief efforts in US history.

New Orleans officials estimated that 80,000 people remained in the city, out of a total population of 480,000. Nagin estimated that 15,000 residents could be evacuated each day.

''The magnitude of our work is unfathomable," Governor Kathleen Blanco said. ''We need a higher power now."

In a plan organized by the Pentagon, four Navy ships were dispatched to the Gulf Coast, along with the hospital ship USNS Comfort, search helicopters, and elite SEAL water-rescue teams.

American Red Cross workers from across the country converged on the region in what the agency called its largest domestic relief operation ever. The State Department spokesman, Sean McCormack, said the US government had received ''a number of offers" of assistance for the search and reconstruction effort, but he did not specify which countries had made the offers.

The Bush administration also decided to release crude oil from the country's petroleum reserves to help refiners whose supply was disrupted by Katrina. The announcement helped push oil prices lower.

If Nagin's fatality estimates are correct, Katrina could prove to be the deadliest hurricane in the United States since a storm in 1900 killed at least 6,000 to 12,000 in Galveston, Texas.

A 1928 hurricane killed at least 2,500 in South Florida. Katrina killed at least 110 people in Mississippi, which had been thought to be the hardest-hit area.

''The situation in all affected areas remains very dangerous," said Homeland Security Secretary Michael Chertoff. ''We will work tirelessly to ensure that our fellow citizens have the sustained support and the necessary aid to recover and reclaim their homes, their lives, and their communities."

The mayor's fatality figures underscored the urgency with which military and civilian personnel are scouring the city for imperiled survivors. Nagin has ordered the entire city evacuated. ''We have to," the mayor said. ''The city will not be functional for two or three months."

As part of the evacuation, officials planned a two-day convoy of 475 buses to carry people who have been sheltered in the Superdome to Houston, 350 miles away. Tempers had begun to flare in the complex, where Katrina punched holes in the roof, and many toilets stopped working. ''We can use the Astrodome as a place for our folks to begin to normalize" and free the National Guard to search for victims and bodies, Blanco said.

To bolster that effort, the US military will send an additional 10,000 National Guard troops to Louisiana and Mississippi, bringing to 28,000 the total number of active-duty Army and National Guard troops deployed in the four-state coast from Louisiana to Florida.

Lieutenant General Steven Blum, head of the military's National Guard Bureau, said that one-third of the National Guard's 21,000 troops will be dedicated to helping keep law and order.

Tim Barnett, a Federal Emergency Management Agency employee from Weymouth, , Mass., said the looting had become so brazen in New Orleans that he had spent part of yesterday trying to recall some of his Boston-based team from the city.

''Right now, it's just mayhem, like rioting stuff," Barnett said. ''We're trying to pull some of our people out."

State officials evacuated the remaining 5,300 prisoners who had become threatened by rising water and power shortages at the prisons in Orleans and Jefferson parishes, a corrections department spokeswoman said.

Previously, a total of 2,300 had been evacuated -- many of them by boat -- by 1 a.m. yesterday.

Amid the continuing horror of the deaths, devastation, and displacement, state and Army officials said that the water level had stopped rising in New Orleans, as waters that the storm surge had pushed into Lake Pontchartrain returned to the Gulf of Mexico.

''The good news is that we're stabilized. Things are looking very positive," state Transportation Secretary Johnny B. Bradberry said. Officials said the water level in Lake Pontchartrain is dropping by a half-inch per hour, and has fallen two feet in the last two days.

However, officials said the lake is still 2 feet above normal levels. Once the levee breaches are repaired, Bradberry said, at least 30 days will be needed to pump the water back into the lake. Several of the city's pumps are not functioning because of high water and power outages.

Around-the-clock work continued in an unprecedented effort to close a breach at the 17th Street Canal levee, through which most of the flood water entered the city.

Major General Don Riley of the Army Corps of Engineers said that 3,000-pound sandbags already have been dropped in the gap, and that Chinook helicopters will drop 1,200 sandbags weighing 20,000 pounds each. Rocks weighing as much as 650 pounds also might be used to repair the breached levees.

''We have not done this before," said Greg Breerwood, a top engineer with the New Orleans office of the Army Corps. ''We're looking at any option before us to stop the breach.

''This seems to be the quickest," he added, ''and that's why we decided to do it. Our goal is to get as much into the breach as possible as fast as possible." For Eileen Duggan Jones, 57, the repairs will not be enough to entice her to return to the city she loves.

Jones, who lived in the French Quarter before she evacuated Tuesday, said: ''I'm going to take myself to higher ground. The city is like a fishbowl. It'll never be the same." Jones, who was rescued by a volunteer in his boat, walked barefoot in the River Center, a convention area that was turned into a shelter for thousands of people displaced by Katrina.

Beside her, a 12-year-old girl, Michelle Cloud, cried as her adult cousin explained that their 30-person extended family was torn about their next move.

Half of them wanted to move closer to relatives in Texas, said Arthur Smith, 38, while the remainder steadfastly wanted to return home to the Lower 9th Ward, a poor New Orleans neighborhood that was savagely hit by Katrina.

''This is like a 9/11 for the South," Jones said.

Stephen Smith and Farah Stockman of the Globe staff contributed. Material from wire services also was used.