Desperate to help his ailing sister-in-law, who had gone five days without kidney dialysis, Samuel Sorapuru tried to flag down National Guard vehicles. He begged ambulance drivers to stop. He appealed to anyone he encountered in uniform. In the end, he stood for an hour on a highway overpass crowded with stranded refugees -- and tried to wave in a helicopter. No luck.

"This," he said, "is total chaos."

Thousands of New Orleans residents remained stranded in a crippled city Thursday as badly overmatched authorities did what little they could and prayed for reinforcements to arrive soon.

Refugees ran short of energy, patience and hope even as fleets of buses hauled thousands out of town on the only passable exit road. Hundreds more in need of medical help were evacuated by helicopter, only to be marooned on stretchers on the crowded floors of the New Orleans International Airport.

Authorities there set up a morgue, and began using it.

Downtown, communication was minimal, leadership distant. There was no central organizing point, no evident headquarters to which a resident could appeal for help or news. Police officers and National Guard members, along with law officers imported from around the state, rarely knew more than what they could see with their own eyes.

Asked how much information she had, Natchitoches, La., probation officer Melissa Murray answered ruefully, "Little to none."

Questions outnumbered answers by a fearsome amount. Demand overwhelmed supply.

"It's heartbreaking. I've never seen anything like it," said Ralph Mueller, a Louisiana parole and probation official who oversaw a crew guarding hundreds of prisoners washed out of the local jail. "People are coming up with babies. A woman just came up, and EMS checked her out and said we needed to help her."

The answer was no.

"We can't take her because -- I hate to say it -- that's not our job today. Our job today is crowd control and inmate control."

Refugees trudging away from flooded homes, hoping for a lift out of town, said the lack of information or any known plan to evacuate them was almost as frustrating as the dearth of food and transportation.

"They need to get on the horn," Valerie Johnson said, pointing to flocks of helicopters working the skies. "They need to use their loudspeakers. The people don't know what's going on. They don't have radios, batteries."

New Orleans was under a mandatory evacuation order and Wilbert Washington simply wanted to know where to go. A nurse by training, a good Samaritan by conscience, Washington all but used up his gas ferrying strangers to places where they might get help, constantly being told to go somewhere else.

He was at the Superdome at 3:30 a.m., he said, when three buses pulled up to collect refugees from the storm. Frustrated, people began banging on the sides of the buses. The frightened drivers drove off. Washington described bodies left in the open at the city's convention center, where thousands of people were told to go, only to find no relief.

On the curb of a littered street, Lloyd Simmons, 68, struggled for breath after a fruitless search for help. An emphysema sufferer, he had medicine and a portable ventilator to help him breathe, but no electricity to make it work. Turned down everywhere he looked, he stood in the road and tried to flag down a column of National Guard transports.

"They wouldn't even stop," said Simmons, returning to the curb. He wondered: Where was the Red Cross, the mayor, the City Council and the government? "They've got to give help to people who need it right now," he said. "Tell me what to do and I'll do it. Tell me where I can get some electricity so I can get some air."

Nearby, Alton Love held the hand of his daughter, Adrian, 6. They spent a day and a night perched on a scorched highway. Another night, they camped on a relative's porch. They saw crowds in the street and lots of armed men.

"These old boys, they have guns. They're taking what they want from anybody and everybody. Where's our government response? They keep telling us they're coming and nobody's there yet," said Love, 38, a plumber. "My little daughter, she's scared to death. I put her on my back -- I'm tired. I don't let on to her I'm tired. Everybody else is gone. We're just left here."

New Orleans police carrying shotguns guarded the entrances to the city's famous French Quarter, where restaurants, bars, hotels and stores remained largely dry and intact. With only a few stragglers left, the streets Thursday stood all but empty. K-Paul's was deserted and boarded up. The same was true around the corner at celebrity chef Emeril Lagasse's NOLA, no longer serving Plaquemines Parish oysters or the shrimp-and-grits entree.

The quarter was not totally without its trademark food smells. Outside an Omni hotel, several New Orleans police officers were grilling spicy steaks on a makeshift sidewalk grill.

"Move on out of here," an officer warned a passerby.

As fat raindrops fell, over on Conti Street, Damian Tenhaaf hoisted steel grates into the streetfront windows of Olde Nawlins Cookery. "Barricading ourselves in," he said, explaining that looters had prowled the neighborhood earlier in the week. "We're going to get this metal on the walls, stack things in front of the door and sit up on the second floor with the guns."

Proprietor Mike Lala intends to wait out any trouble that emerges -- and shoot anyone who might have other ideas.

"This building's been here since 1838," said Lala, a Korean War vet and former television cameraman. "I figured the building would be all right, but I never even thought about looters. All I can do is make it difficult for them."

Lala choked up. Continuing after a moment, he said, "I can't believe I'm getting emotional about this stuff."

On Canal Street, Al Goldberg, a prosperous dentistry professor with heart trouble, appealed to a city police officer for help with his luggage. A few hours earlier, the Ritz-Carlton, evacuating the hotel, had dropped nine of its most vulnerable guests on a sidewalk. They were told a bus would pick them up.

The bus never came. Goldberg, his wife and the others wanted to get back through the floodwaters to the hotel, or pay someone to drive them to Baton Rouge. There were no takers.

"We can't stay here in the dark," said Michele Anderson, another guest. "We're sitting ducks."

Outside, sidewalks were packed with people without food, water or medical care, and there was no sign of police. Thousands of storm refugees had been assembling outside for days, waiting for buses that never came.A dead man sits on a lawn chair at the New Orleans Convention Center as other victims of Hurricane Katrina pass by.