Houstonians mobilized for an influx of as many as 25,000 trapped refugees from New Orleans on Wednesday as this oil city opened its pocketbook, its shelters and its vacant American landmark, the Astrodome, to its homeless neighbors.

From government officials to ordinary residents, so many of those involved in the hurricane-relief effort said they knew it could have been them had the wind been blowing down the Gulf Coast toward Texas on Monday.

"We realize that by the grace of God, we could be the ones that have this extra need," Texas Gov. Rick Perry (R) said, announcing that hundreds of buses would soon be arriving carrying hurricane survivors to Houston from the sweltering Superdome.

The city, schools, churches, hotels, hospitals and dozens of relief agencies organized to accommodate the refugees inside the Astrodome, which has been used only sporadically since baseball's Houston Astros left in 1999 for more modern quarters downtown.

Red Cross contractors prepared to move thousands of cots into the 70,000-plus capacity domed ballpark dubbed the Eighth Wonder of the World when it was built in 1965.

A catering company set up makeshift kitchens. And the air conditioning, so desperately missing in New Orleans, was turned on.

"We're essentially picking up a small city and inserting it into Houston," said Frank Michel, the city's communications director. The first buses from New Orleans were expected to arrive Wednesday night, although officials said the trip could be delayed.

Once the buses arrive, officials said, the challenges will be huge, identifying sick or emotionally traumatized travelers, helping them to cash checks, find ATMs and telephones to contact their families.

There will be tight security around the Astrodome but no curfews, Michel said.

The bus arrivals represent a second wave of storm victims in Houston. Thousands of families drove here seeking shelter in the days before Katrina hit, staying with friends and family or in local hotels, which are now almost booked.

All around the sprawling city, the country's fourth-largest, people rose to the sudden challenge before them.

A local CBS television affiliate held a telethon to raise money for the refugees, local hospitals began evacuating critically ill patients from Louisiana and Mississippi, and Radio Saigon Houston, a local station that broadcasts in Vietnamese, announced that Vietnamese speakers would take in hundreds of Vietnamese storm victims.

The Houston Independent School District, which started classes on Aug. 15 and has 209,000 students, announced that it would temporarily enroll students evacuated from their homes.

"We're a large district, and we're accustomed to doing things on a large scale," said Harry Abbott, the school district spokesman. "We feel like we have the resources and the space."

Many of the system's 305 schools have excess capacity, Abbott said.

Under Texas law, the newcomers will qualify as homeless students for 30 days, without needing their academic or medical records transferred. But after that, things could get complicated.

"We know there's a good chance these kids might be here a couple of months or more," he said.

Since the Astros left for the Minute Maid Park, the Astrodome has been pressed into service sporadically for high school football games, trade shows and the annual Livestock Show and Rodeo.

But the city is debating a permanent use.

"Thank God it's being put to good use and helping people going through a tragedy instead of becoming a bingo hall," said Mary Joyner, a reservation agent at the Hotel Icon downtown.