Thousands of evacuees, exhausted and frustrated after days trapped in flooded New Orleans, continued to pour into Houston and other cities in Texas on Saturday, rapidly filling enormous arenas and small shelters in an extraordinary exodus of humanity that has quickly strained the capacity of the Lone Star State.

Over the past six days, Texas has mobilized its emergency relief operations almost as if Hurricane Katrina slammed into its borders, rather than the neighboring eastern states, and in a very real sense Katrina has hit Texas with massive force. About 240,000 Louisianans have found sanctuary in the Lone Star State in hotels and large shelters, state officials said. Many more are in church-run shelters and even some in private homes. Officials are scrambling to stay ahead of what they anticipate could be a long-term relocation of humanity.

Houston has become ground zero for the exodus, with 100,000 to 200,000 of the total number of refugees in the state sheltered here. To cope, officials have built a virtual organization from scratch, blending the public and private sectors, nonprofit groups and churches to handle the evacuees' needs.

Almost overnight, officials established one of the largest hospitals in the state to cope with indigent and ailing exiles, and they are planning how to move the evacuees from temporary shelters including Houston's Astrodome and the George R. Brown Convention Center into more permanent housing. In coming days, Houston area schools are expected to absorb 6,000 to 8,000 students from Louisiana.

By Saturday, state officials said they were close to capacity and urged the Federal Emergency Management Agency to start diverting evacuees scheduled to move to Texas to other states. Over the past two days, Texas Gov. Rick Perry (R) and his staff have contacted the governors of Michigan, Oklahoma, Iowa, Utah and West Virginia urging them to take some Louisiana evacuees.

"Texas is committed to doing everything it can to help our neighbors from Louisiana, but we want to make certain that we can provide them with the medical care, food, shelter, safety, education and other services they need to start getting their lives back together," Perry said in a statement. "Local officials are beginning to notify us that they are quickly approaching capacity in the number of evacuees they believe they can assist." Some officials in East Texas, however, said they still had adequate space in their shelters as of the end of the week.

In the aftermath of a storm that has raised pointed questions about the adequacy of the response by officials in Washington and Louisiana, Texas so far has avoided the finger-pointing, complaints and social breakdown that have marked the situation in New Orleans while mobilizing rapidly and unexpectedly for the evacuee influx.

The response has not been flawless. The Astrodome reached capacity far faster than expected, and long before the bus convoy from New Orleans had finished emptying the Superdome and convention center there. Tempers flared and city and county officials quickly found more space for temporary housing. Dallas officials sent out alarms early Saturday saying they would soon reach their capacity to handle the evacuees on the way to their city. Bottlenecks in the bureaucracy have complicated efforts to qualify Louisianans for assistance.

On the whole, however, Texas appears to be weathering the first wave of a crisis thrust upon the state by the accident of geography, helped by their experience in dealing with Tropical Storm Allison in 2001, which put 50,000 Houston homes underwater.

Houston Mayor Bill White said in a telephone interview that the city began mobilizing at a new level of urgency when the levees in New Orleans were breeched. "A lot of us understood what that meant, that it was a different issue than a weather issue, that we were dealing with the virtual destruction of a major American city."

State officials estimated Saturday that 100,000 Louisianans were in Texas hotels and motels, 123,000 in 97 shelters around the state and another 16,000 scheduled to arrive by bus or airplane by day's end.

The Astrodome is now home to about 15,000 people, rather than the 23,000 originally envisioned. Another 11,000 are being housed in ancillary buildings. Another 8,000 are in the city's convention center. But even as the influx continues, officials are beginning to move people to more permanent housing, a few hundred at a time.

"This is a shelter, it's not a home," said Harris County Judge Robert Eckels, the county's chief executive. "When you put 15,000 people together in a single location, even if you've got water and food and air conditioning and a place to lay your head, it is still very close quarters. It is not a healthy psychological environment for a long period of time. We need to move those people as quickly as possible into more permanent housing."

Many officials say they are working under the assumption that many of the new arrivals may stay in Texas for a year.

Officials in Harris County, which owns and operates the Astrodome, said the sports stadium's parking lot is serving as a depot for buses bound for southeast Texas. Many will be redirected to shelters in Corpus Christi, San Antonio, Lubbock, Huntsville and other cities, Paul Bettencourt, the county's tax assessor-collector, said.

Medical officials said they are keeping an eye out for contagious diseases among the new Astrodome residents, but have not come across any so far. They were giving tetanus shots to thousands of evacuees, many of whom came into contact with contaminated flood waters in Louisiana. Houston police reported a small number of minor arrests.

"We want to make people feel and understand that things here are orderly, and that we have things under control," Assistant Police Chief Brian Lumpkin said. Five hundred law enforcement officers are patrolling around the dome.

Before they could think about finding new jobs or schools for their children, the evacuees were trying to find relatives they had not heard from since the storm hit. The Red Cross in Houston announced the creation of an on-line registry for those outside New Orleans to post names of missing family members, and relief workers inside the Astrodome walked around with laptop computers to try to match names with people. A bulletin board in the stadium was growing hourly with scraps of paper listing lost relatives. A room was set up for lost children.

"We think we are finally getting the name of everyone who is in Houston in our database," said Chris Johnson, a spokesman for the Red Cross Southwest region.

Officials face the challenge of qualifying the evacuees for a variety of assistance programs, from housing vouchers provided by FEMA to federal food stamps or Medicaid. In Houston, officials quickly established a system to provide prescription drugs to evacuees who had no prescriptions and no money.

The Texas Health and Human Services Commission, said the state has registered almost 27,000 Louisiana families for food stamps in the past two days. Albert Hawkins, the executive of the agency, said the processing had gone ahead even with some important questions -- will Louisiana or Texas be required to pick up the state share of the costs, for example -- to be resolved later.

In Houston, officials have tapped an outpouring for support from volunteers and hope to use that goodwill to create partnerships between Houston families and relocated Louisiana families. White said the city is seeking 50,000 families to pair with evacuees to offer advice and mentoring.

How much the relief operation will cost Texas is another unknown. The federal government ultimately will bear much of the expense, but no one can estimate what the overall costs will be.

The evacuees have landed in Texas cities after unpredictable journeys from Louisiana. The chartered American Airlines jet that brought Mary Harris and six members of her family to San Antonio early Saturday was originally headed to Austin, she was told. "I swear, honey," Harris recalled, "ten minutes before we landed, they said, 'Nah, we're taking you folk to San Antonio.' " Charles Lee, 80, had a similar change of destination on a bus. "We was heading to that Astrodome, in Houston," Lee recalled of the day-long ride from New Orleans. "And when we got there, they said it was full up. So we kept a-coming' to this big place."

"This big place" is the former Building 1536 of the former Kelly Air Force Base, an abandoned defense facility that San Antonio has converted to a business park named KellyUSA. The evacuees' new home is a quarter-mile-long structure that has been cleaned, carpeted, and equipped with thousands of cots.

The power and water are in working order, and volunteers freely distribute blankets, toys, newspapers, food and drink. All of which makes Building 1536 a relative paradise to evacuees who spent four or more hellish days in dark, fetid shelters back home.

And yet, the more comfortable surroundings have given some of the new residents the time to worry about the things they left behind. "Now that I can just set somewhere for a while," Charles Lee, "I have to start wondering whether I've got anything left at all.

Balz reported from Washington. Staff writer T.R. Reid in San Antonio contributed to this report.

An unidentified man tries to sleep with a paper plate over his face to block the lights. The Astrodome filled faster than expected, so displaced people were shipped to other Texas sites.Sadie Davis, 70, who arrived from New Orleans two days ago, checks her medicine on a cot at the Astrodome.