Relief gave way to despair Tuesday for many survivors of Hurricane Katrina. Facing days of misery and uncertainty, awaiting clearance to return to damaged or destroyed homes, some broke down in tears.

"Everything is totaled, everything is destroyed, everything is gone," said Thomas Green, rescued by a boat along with his family from the attic of their flooded one-story house in New Orleans.

In the Louisiana Superdome, where thousands of residents unable to evacuate the city had taken refuge, a woman cried as a TV newscast detailed the devastation and reported that residents would be blocked from returning to their neighborhoods until next week.

Many thousands of people will need temporary shelter for weeks, possibly months, said Mike Brown, director of the Federal Emergency Management Agency. Many areas also face prolonged power outages.

Along the Mississippi Gulf Coast, the hardest hit region, evacuated residents struggled to come to terms with the extent of the destruction and the massive cleanup and rebuilding efforts that lie ahead.

"Now we're trying to salvage just a few memories," said Dorothy Loy of Pascagoula. "It's so depressing, really, because you have no address."

Alex Romansky, a Gulf Coast resident for 30 years, said he was unlikely to stay. "My inclination, after seeing this kind of storm damage, is that we don't want to live here anymore," he said.

Farther north in Mississippi, at an intersection outside Hattiesburg, dozens of cars were lined up to get gasoline at a convenience store.

Jake Walker, 34, and his wife, Shelia, 41, of Saucier, had evacuated from their mobile home with their dog and two pet doves, Romeo and Juliet. Their pickup truck was full of furniture. "My home probably ain't there," Jake Walker said.

Bill Higginbotham, a 91-year-old retired carpenter from Biloxi, and his son-in-law had driven up from the coast seeking to buy gasoline.

"Most probably I don't have a home anymore," he said of the single-story, timber-frame home he built in 1940. "I wanted to live, but after this I don't want to live no more."

Another Biloxi resident, 19-year-old Landon Williams, didn't heed the evacuation orders and had to swim for his life after floodwaters smashed into his apartment in the Quiet Water Beach complex where numerous other residents are believed to have died.

"I lost everything. We can't even find my car," said Williams, a construction worker. "I think I'll move on to North Carolina and do some work over there. I can't take it here any more — not after this."

Louisiana Gov. Kathleen Blanco empathized during a news conference in Baton Rouge after surveying the devastation and encountering survivors with "despair in their faces."

"This is not going to be an easy time for any of our citizens who've been affected . . . . The dimensions are unfathomable," she said. But she said the city would survive and rebuild.

Back in New Orleans, Thomas Green tried to look past the disaster.

"I guess we'll just have to start from scratch, start all over," he said, "that's all we can do."