A Sept. 2 article describing the huge number of people displaced by Hurricane Katrina should have included a comparison with the 1927 flooding of the southern Mississippi River, which drove 325,000 to Red Cross shelters and may have uprooted as many as 700,000 altogether. This is the closest parallel to Katrina's impact. (Published 9/5/2005)

The largest displacement of Americans since the Civil War reverberated across the country from its starting point in New Orleans yesterday, as more than half a million people uprooted by Hurricane Katrina sought shelter, sustenance and the semblance of new lives.

Storm refugees overwhelmed the state of Louisiana and poured into cities from coast to coast, crowding sports arenas, convention centers, schools, churches and the homes of friends, relatives and even strangers. Red Cross officials reported that every shelter in a seven-state region was already full -- 76,000 people in Alabama, Mississippi, Florida, Georgia, Texas, Arkansas and Louisiana. Hundreds of miles from New Orleans, hotels were jammed or quickly filling.

Rich and poor alike, they found themselves starting over. The former began buying new houses and leasing new office space. The latter waited in lines for a bar of soap or a peanut butter sandwich.

Katrina has scattered more than twice as many people as the San Francisco earthquake of 1906, and unmoored more people in a few days than fled the Dust Bowl in the 1930s. Estimating from census data, about 150,000 of the displaced lived below the poverty line even before they lost everything. Far more than 50,000 of them are past retirement age.

Cities and hamlets, charities and individuals stepped up to help. In Washington, District officials made plans to open a shelter in the D.C. Armory, and 415 retired veterans were moved from the Armed Forces Retirement Home in Gulfport, Miss., to a similar facility here.

"The biggest issue we're faced with is handling the volume of people," said Margaret O'Brien Molina, a spokesman for the Southwest region of the American Red Cross. "Just identifying their needs is so complex."

In Baton Rouge and other Louisiana cities, the influx was dangerously straining services, officials warned. Armed guards were stationed at food distribution sites, and Baton Rouge police chief Jeff LeDuff said the city's hospitals might have to be barricaded to prevent desperate storm victims from continuing to swamp emergency rooms. The city's sanitation system is overloaded, garbage collection has soared, gasoline is scarce.

"Instead of water flooding in, we've got people flooding in," said Mike Walker of the East Baton Rouge Parish Council. "The levee of people broke."

Where to go? What to do? They needed food, water, medicine, beds, showers, toilets, clothing, jobs, schools, friends, diversions. Where to begin?

For many of the impoverished refugees from the Louisiana Superdome in New Orleans, the first step into the future led to a strip mall near the Astrodome, which transformed into a bazaar of free ham sandwiches, water, diapers, baby formula and other supplies brought by volunteers.

Gaynell Warden, 46, stood in her pajamas, 350 miles from home -- make that former home. For now and the knowable future, she lives in a new town of 25,000 made up of cots in an old stadium. "My son is missing. I don't know if he's dead or alive," she said.

Allen Porter, 18, sat in a hotel lobby in Hot Springs, Ark., 530 miles from his former home. His parents were out looking for a condominium while their son tried to sort out the confused picture that had seemed so clear and glittering just days before. Senior year, top of his class at Jesuit High in New Orleans, Porter was a bit annoyed when his mother insisted on evacuating. He packed his iPod, "Wuthering Heights," and his applications to places such as Princeton, Yale and Virginia. Now his high school was reportedly under 13 feet of water, deep enough to drown his transcripts, and his khaki-clad buddies were scattered to the winds.

"It could get lonely over time," he mused via the Internet.

Porter was probably wise to take the long view, because the few lessons available in upheaval of this scale suggest that the metropolis flung apart by the hurricane may still be in pieces years from now. More than 300,000 Japanese were left homeless by the Kobe earthquake in 1995 and some were still in makeshift camps three years later. Closer to home, the sudden influx of125,000 Cubans in the 1980 Mariel boatlift was only partially absorbed by families and volunteers across the country; some of the refugees remained in camps into the late 1980s.

Herbert McKnight, 44, had no intention of waiting for New Orleans to be restored. "The way I'm looking at it, I don't have a job and I don't have a home," he said in Houston, where he and 20 members of his extended family were among the tens of thousands of displaced people occupying virtually all of the city's 55,000 hotel rooms. McKnight, an accountant, said he was desperate to find work and move into an apartment in the Texas city.

Mostly, though, it was a matter of coping with the here and now.

Internet bulletin boards buzzed with offers of spare bedrooms and pleas for volunteers. "I have 11 family members arriving," a harried host in Maryland began, and "a rental property in Capitol Heights, MD to put them in. . . . However, it is currently undergoing renovations and is not quite habitable yet . . . I need donations."

And: "I am in Kewanee, IL. a small rural community in Illinois. . . . I can fit 2-4 comfortably . . . 6-8 in a squashed condition."

School boards in state after state dropped their normal admission rules to make room for more than 100,000 school-age children from New Orleans and other storm-wrecked communities. Colleges and universities offered to reopen their rolls to take in about 50,000 displaced students.

But for some of the hardest-hit evacuees, such concerns seemed light years away. Those who were not moved to the Astrodome fanned out across Louisiana, swelling cities and towns to the bursting point and sorely testing the capacities of their neighbors.

In Sorrento, approximately 50 miles northwest of New Orleans, there was "looting everywhere, all over the place. There is chaos everywhere right now," said Police Chief Earl Theriot. "There's a bunch of fights. All our shelters are full. The gas rationing is getting out of hand."

Theriot spent part of his day dealing with the death of an elderly woman on a bus full of nursing home patients who were traveling without any attendants or medical personnel.

Up the road in Alexandria, where the sometimes surly storm-tossed were being housed in an abandoned Wal-Mart, police chief Daren Coutee issued a plea for authorities in New Orleans to search each evacuee for weapons before sending them along.

In Baton Rouge, city officials said that 20,000 refugees are being housed in official shelters, but they believe that's just the tip of the iceberg. Thousands more are thought to be staying in private homes, hotels and other facilities. And they are braced for more.

Rep. Richard H. Baker (R-La.) said he planned to ask for temporary housing facilities from the Defense Department, the Department of Homeland Security and private companies and realtor groups. "Portable barracks, mobile homes, vacant commercial structures -- whatever can house people in humane conditions," he said yesterday.

More than 800 people are currently sleeping on inflatable beds on a gymnasium floor at Louisiana State University-Shreveport, where their living quarters aren't much larger than an average car. All of their belongings -- perhaps some clothes, toiletries and an old a photo album -- are stacked by the beds. There's no other space for storage. Beds are crammed in like puzzle pieces, covering nearly every bit of the hardwood floor.

Some residents plan to live in the gymnasium for at least the next month.

"When my family first came here, I was like, 'No way. I'm not staying at a shelter. I'm not going in,' " said Latrice Alexander, 35, who fled here from New Orleans on Sunday. "I sat in the parking lot for like an hour and refused to come in, and now this place is basically home.

"It's tough. When you want to shower, there's usually a line of 10 people in front of you. There's never anything to do. You get up. You eat. You take a walk. Then you come back to your little bed."

The scene is repeated in towns and cities across thousands of square miles.

By midday yesterday, more than 1,000 refugees had found Starkville, a university town in northeastern Mississippi, according to Duane Tucker, disaster chairman for the local Red Cross chapter. "All the hotels in town are full, we've got people staying with relatives, and about 40 people from New Orleans living in a church shelter." And the problem is likely to worsen as middle-class families in hotels run out of money.

"I can't see the end," Tucker said.

A major city, thrown to the winds. No one spared. Not the prosperous DeLongs, a Garden District family of lawyers and university administrators now dispersed from Texas to the District. And not the huddled masses in the Astrodome, suffering from dehydration, diarrhea, malnutrition and other problems.

In Houston, Harris County Chief Administrator Robert Eckels hoped that the Astrodome would not be a city for long. "This is not a place you want to be living for months with that kind of crowd. We want these folks to move on." Still, plans are being hatched to open a school there. And Walker, the Baton Rouge council member, is predicting that his city of 217,000 could double in size as refugees come to realize that "they have no place to go back to for years."

"This is not a one-day or a one-year crisis. This is changing people's lives," said Baker, whose district includes Baton Rouge. "This is a societal problem of a magnitude that America has never seen."

Salmon reported from Baton Rouge, La. Staff writers Peter Whoriskey in Baton Rouge; Sam Coates in Sorrento, La.; Lisa Rein in Houston; Eli Saslow in Shreveport, La.; and Ylan Mui, Robert Pierre and Neely Tucker in Washington contributed to this report.

Thousands gather at a evacuation staging area along Interstate 10 in Metairie, La. Katrina has uprooted more than half a million people. Therapist Howie Brownell talks to a family at the Hirsch Memorial Coliseum in Shreveport, La.Darlene Humphrey, foreground center, a nurse with the Veterans Affairs Medical Center in Alexandria, La., tends to a patient from New Orleans.