Seventy miles west of New Orleans, the state capital of Baton Rouge and its surrounding parish received its own storm surge overnight: a huge wave of displaced people, dragging their anger, misery and desperation along with them.

In a day, this city has become the largest in Louisiana, and grim local officials here predicted it would double in size, to about 800,000, permanently. "The Baton Rouge we live in and grew up in is no longer," said city councilman Mike Walker. "These people are here to stay, perhaps forever."

City police chief Jeff Leduff said buses and volunteer drivers Wednesday evening began picking up stranded New Orleans residents from the highways and then "just dropping them off wherever they see a gaggle of lights, any neighborhood, any store."

About 3,000 refugees suddenly appeared about midnight on the campus of Louisiana State University, where a shelter already was at capacity. They were turned away. Most of those 3,000 eventually made their way to the emergency rooms of the area's three biggest hospitals, where "they created extreme chaos and disturbance" throughout the night, said Dr. Louis Minsky, medical director for East Baton Rouge parish.

There were reports of attempted carjackings at 24-hour gas stations. Authorities decided to impose a 10 p.m. cutoff for gas sales.

Sheriff's deputies were dispatched as armed guards for grocery warehouses, and police stepped up around-the-clock controls downtown, where Gov. Kathleen Babineaux Blanco, Sen. Mary Landrieu (D-La.) and FEMA director Michael Brown are hunkered down.

Shortly before noon Thursday, police and SWAT teams with automatic weapons moved to secure several city blocks near the largest shelter, the River Center, which houses about 5,000 refugees.

Officials made a decision to allow non-essential workers from the city government building to go home for the day, said Michael Smith, a spokesman for the emergency operations center here, and officers escorted those who left to their cars.

"We called for additional sheriffs and city police to secure the area and let those people out," he said. He said rumors of looting and mayhem were unfounded and were spread through local talk radio. Officials here, he said, hope the display of force would show that government here, unlike in New Orleans, was in control.

The parish has several Red Cross-run shelters already filled up with at least 10,000 people, and security is an increasing problem in them, as well as a strain on paramedic responders.

"Everybody in the River Center," the largest shelter, "has a cell phone, and when they run out of medicine, they just call 911," said a spokesman for the city's emergency services department.

With a new month beginning Thursday, hundreds of the newly homeless and poor crowded up the area's food-stamp offices to start applications.

In addition, others are coming to town looking for opportunity. "People are showing up with suitcases and suitcases of cash, offering to buy houses and real estate on the spot," said Walker, who is also a real estate broker.

On top of all that, 55,000 customers remain without power throughout the parish, the schools remain closed through Tuesday and traffic is jammed and stores are overrun.

In a morning briefing at the Emergency Command Center near the airport, nearly two dozen officials from every public agency gave updates and shared information, as they have each day since before Katrina struck.

Every change in plans has a ripple effect into every other agency, said Irma Plummer, the chief administrative officer for East Baton Rouge Parrish, in unanticipated ways. "People come here and find they have no money, and all the agencies on this corridor are going to be affected," she told the group.

"The domino effect is tremendous. We can't move fast enough to rebuild our infrastructure to respond, so you have to be creative."