With much of New Orleans under floodwaters and power supplies deteriorating, relief officials have decided to move 25,000 people -- most of them being sheltered at the city's Superdome -- to the Astrodome in Houston, officials said Wednesday.

The refugees from Hurricane Katrina will make the 350-mile trip in a bus convoy that is scheduled to start running Wednesday. Under normal conditions, the trip takes about 5 1/2 hours.

"We can use the Astrodome for our folks to begin to normalize," Louisiana Gov. Kathleen Babineaux Blanco (D) told a news conference in Baton Rouge. "They will receive all these evacuees. This is going to help us immensely."

Dwight Landreneau, secretary of the Louisiana Department of Wildlife and Fisheries, told the same news conference that water levels in New Orleans appear to have stabilized.

Blanco said rescue teams have plucked 10,000 people from attics and roofs after they were stranded there by the floodwaters.

She said she had talked to Texas officials and appealed to the White House for help. "I've asked the president to give us all the resources possible -- today," she said.

Officials said 23,000 people would be taken from the Superdome and that the evacuation could take as long as two days to complete. They said some of the logistics depend on the extent of the flooding around the Superdome; they hope buses can be brought up to the building.

The Federal Emergency Management Agency (FEMA) is providing 475 buses for the convoy, the Associated Press reported. Officials said all the buses would not necessarily be on the road at the same time.

Texas Gov. Rick Perry (R) said the schedule of the 40-year-old Astrodome has been cleared through December to house evacuees.

"In the next 24 hours, I would guess, we're going to see individuals arriving at the Astrodome," he told a news conference. "We expect there's going to be a growing need for shelters" beyond the stadium. He added that Texas schools would be opened to the children of the refugees.

"This will put a strain" on the Texas school system, he said, but it has already started arranging for extra textbooks and classrooms.

Perry said he has also mobilized a "special medical unit" of the Texas National Guard. "We realize that by the grace of God, we could be the ones who have this extraordinary need," he said. "We're going to get through this together."

The Astrodome, the first ballpark with a roof over its playing field, originally housed the Houston Astros and Houston Oilers, but it has not been used for professional baseball or football since the late 1990s. Owned by Harris County, Tex., the stadium seats more than 62,000 people when configured for football, has central air conditioning and covers 9 1/2acres of ground. It sits in the center of a flat, paved 260-acre property with parking for 30,000 cars.

The Astrodome is still used for about 300 events a year, the biggest of which is the Houston Livestock Show and Rodeo in March. It was scheduled to host a college football game between the University of Houston and Oregon Thursday and the Big 12 Conference Football Championship on Dec. 3.

Carrie Martin, a spokesman for the American Red Cross in Washington, said at mid-morning that the plans for the evacuation were still being made, but the Red Cross, through local affiliates, would handle the operation. She said she expected it would begin in the next 12 to 24 hours.

How people will be extricated from the waters of New Orleans remains a question.

Next door in Mississippi, Gov. Haley Barbour (R), reported that 18-wheelers bearing essential supplies such as food and water were on the way to the coast after crews from across the country succeeded in clearing trees, debris and layers of muck off some of the highways.

In Washington, Energy Secretary Samuel W. Bodman, as expected, said in television interviews that the Bush administration will release oil from federal petroleum reserves to help refiners affected by Hurricane Katrina. A formal announcement was expected later in the day.

He spoke as crude oil and gasoline prices hit new records because of disruption in the supply chain and as the credit-rating agency Standard & Poor's estimated that the economic impact of Katrina could shave "a few points" off the nation's primary measurement of economic output, the gross domestic product.

In Baton Rouge and here in Alexandria, a city in the middle of Louisiana about 175 miles northwest of New Orleans, officials were bracing for a predicted influx of tens of thousands of evacuees to Red Cross and community shelters. Some were people who left New Orleans before Katrina hit, raising questions about where others would go.

A few arrived Tuesday night, escaping rising floodwaters in New Orleans.

Among them were Byron Allen and eight relatives, who left for Alexandria Monday after the water started rising with the breach of levees holding back Lake Pontchartrain.

"We just heard that Alexandria was the safest place to be," he said. However, Allen said, his wife and three children were still trapped in New Orleans, and he had been unable to reach them because of the flooding.

Margaret O'Brien-Molina, a spokeswoman for the Southwest Red Cross based in Alexandria, said that the shelters as far away as Arkansas and Texas are filling up with people who had left New Orleans before Katrina hit.

She said many had moved to homes of friends or to hotels and are turning up at shelters as they overstay their welcomes and run out of money.

"These people have no place to go back to," she said.

There were no further reliable figures on the number of dead, although rescue workers had started going house to house in some communities with crowbars to check for people, living or dead.

Nor was there any visible progress in plugging the levee that began flooding New Orleans Tuesday. Gov. Blanco said on NBC's "Today" program that repairing the levee presented a "logistical nightmare."

"We're working against a lot of odds," she said. "A great hole has dug itself out where the breach occurred. Sand bags are of no use. They get swallowed up into a black hole."

She said engineers were contemplating dropping "large concrete pieces" into the area in an effort to plug the leak.

To repair one of the levees holding back Lake Pontchartrain, officials late Tuesday dropped 3,000-pound sandbags from helicopters and hauled dozens of 15-foot concrete barriers into the breach, Maj. Gen. Don Riley of the U.S. Army Corps of Engineers told the Associated Press. Officials also had a more audacious plan: finding a barge to plug the 500-foot hole.

Riley said it could take close to a month to get the water out of the city. If the water rises a few feet higher, it could also wipe out the water system for the whole city, New Orleans' homeland security chief Terry Ebbert told the AP.

The release from the Strategic Petroleum Reserve is designed to give refineries in the Gulf Coast area a temporary supply of crude oil to take the place of interrupted shipments from tankers or offshore oil platforms affected by the storm.

The government's emergency petroleum stockpile -- nearly 700 million barrels of oil stored in underground salt caverns along the Texas and Louisiana Gulf coast -- was established to cushion oil markets during energy disruptions.

The production and distribution of oil and gas remained severely disrupted by the shutdown of a key oil import terminal off the coast of Louisiana and by the Gulf region's widespread loss of electricity, which is needed to power pipelines and refineries, wire services said.

Energy Secretary Bodman, speaking on CNBC, said the decision to release reserves was made late Tuesday.

Gasoline prices, which closed up 20 percent Tuesday on the New York Mercantile Exchange, continued climbing Wednesday, the AP said. Unleaded gasoline was trading at $2.5585 a gallon by midday in Europe, up more than 8 cents for a new record.

Mississippi Gov. Barbour said he hoped his state had reached a "turning point" with the clearing of some roads and the impending arrival of relief supplies.

"We've had crews come in from all over, God bless them," he said on NBC's "Today" program. "We've turned the first corner, but there are a lot of corners left to go."

In Alexandria, officials opened an 8,000-seat enclosed stadium, the city convention center and an exhibit hall, as well as a city-owned barn for displaced pets.

They also began training hundreds of Alexandria residents on how to staff shelters, while area churches opened their doors to those fleeing the catastrophe.

"It seemed like yesterday people were out on the street saying 'ha ha ha, nothing happened,' " said Rev. Perfeto Esquibel, pastor of Christian Worship Center in Alexandria, which is opening its sanctuary and gymnasium to evacuees. "And now it's death and destruction."

"I just hope they're all right," he said softly, tears in his eyes.

Whoriskey reported from Baton Rouge, La. Staff Writer Ann Gerhart contributed from Baton Rouge. Branigin reported from Washington. Staff writers Lexie Verdon and Fred Barbash contributed from Washington.