Georgia officials warned worried residents to wait for the floodwaters to recede before checking out their damaged homes, and in Tennessee, a retirement center was evacuated.
Torrential Southeast rains soaked the region for days, knocking motorists from cars and splitting at least one mobile home. A Tennessee man who jumped in the floodwaters was still missing.
Washed-out roads and flooded freeways around metro Atlanta caused commuters headaches and hundreds of residents sought refuge in shelters. About 120 residents of a Tennessee retirement center were evacuated by boats and trucks and others were ferried from low-lying neighborhoods and motels in a Chattanooga suburb as two nearby creeks continued to rise.
Georgia emergency officials said they were confident those in immediate danger had been evacuated, but were concerned about residents attempting to return to their homes too soon.
"We had people who were out safely but decided they wanted to get back in danger," said Charley English, head of Georgia Emergency Management Agency.
Gov. Sonny Perdue asked President Barack Obama to declare a state of emergency in Georgia and urged residents to stay away from flooded areas. Officials were beginning to assess the damage and did not provide a financial estimate.
"I want to plead with you to give these waters time to recede," Perdue said. "Rescuers are putting their lives at risk to try to get someone out who foolishly drove through rushing waters."
The skies were clear and even sunny in parts of Georgia on Tuesday. Most of the rain eased overnight, but some residents in some areas woke up to new flooding.
In west Atlanta, resident Garrett Nail and several neighbors worked several hours to clear a tree that had blocked a road to their community.
"It was troubling at first. There was no power. We knew people had to get to work, school, doctor's appointments," said Nail.
"We were left with two options. Help ourselves or wait on the government. We obviously decided to help ourselves."
State climatologist David Stooksbury said the ground was saturated and unable to absorb the large amounts of water.
"It just takes time for that water to work through the system," he said.
About 12,000 Georgia Power customers were without power. Scattered outages were also reported in North Carolina.
Over 300 people were being helped at shelters across the Atlanta and north Georgia region, according to Red Cross officials.
One of the largest shelters was at the Cobb County Civic Center, where Shirley Jones joined others sitting on green cots, chatting about the fate of their homes. Around them, children played games, oblivious to the destruction.
"When I saw the water rising, it brought back bad memories," said Jones, who lived in New Orleans during Hurricane Katrina. The 72-year-old had moved to the area two months ago.
Jones said rescue efforts this time went much more smoothly. A boat retrieved her from a family member's house.
Before being evacuated, Cordell Albert and her husband Christopher moved their valuables to the second floor of their Powder Springs home. The couple waded through knee-deep water before a raft picked them up.
"I feel lost," she said. "I feel homeless."
Seven people have died in Georgia since Sunday night, including a toddler swept away from his father's arms after a swollen creek ripped apart their trailer home.
The eighth victim, a 22-year-old Alabama man, drowned when a pond's rain-soaked bank collapsed beneath him.
In Chattanooga, Tenn., Sylvester Kitchens, 46, was still missing two days after betting onlookers he could swim across a flooded ditch next to his house.
Several others who died were motorists whose cars were overtaken or trapped by fast-rising floodwaters.
After several days of steady rain that dropped up to 20 inches in one place, forecasters said there was a chance of more light showers.
Days of downpours and thunderstorms saturated the ground from Alabama through Georgia into eastern Tennessee and western North Carolina, just months after an epic two-year drought in the region ended following winter rains.
As Tuesday rush-hour began in Atlanta, Interstate 20 west of the city was closed in two spots by water spilling over the major artery for suburban commuters. Portions of at least two other freeways in the metro area were also closed, as was I-75 in Houston County in central Georgia.
Hundreds of roads and bridges were under water or washed out, including 17 bridges on state and interstate highways.
--- Associated Press writers Greg Bluestein, Johnny C. Clark, Errin Haines and Dionne Walker in Atlanta, and Bill Poovey in Chattanooga, Tenn., contributed to this report.