Hurricane Irma is now wreaking havoc in in South Carolina after causing at least eight deaths in Florida and Georgia.
A flash flood emergency was issued for Charleston this afternoon as Irma, which was downgraded to a tropical storm this morning, batters the Southeast with torrential rain and dangerous storm surges.
As of 5 p.m., Irma was about 150 miles south of Atlanta, moving north-northwest at 17 mph with sustained winds of 50 mph.
A tornado watch across parts of the Georgia and South Carolina coast, including Savannah and Charleston, has been extended into this evening.
Irma could also bring 50 to 60 mph wind gusts and flooding to Atlanta tonight. A wind gust of 64 mph had been reported Atlanta by Monday afternoon.
Tropical storm warnings remain in effect for parts of northern Florida, eastern Alabama, Georgia and southern South Carolina. On Monday, President Donald Trump has approved a state of emergency declaration in Alabama after speaking to Gov. Kay Ivey on the phone the day before, the White House announced.
This morning, water raced through the streets of Jacksonville, Florida, bringing record levels of storm surge along the coast and inland rivers.
Tallahassee appears to have been spared from injuries, major damage or flooding, the emergency management director for Leon County told ABC News this morning. The major issue there are power outages from trees that fell over power lines.
Bumper-to-bumper traffic was seen on Interstate 4 heading toward the west coast of Florida as those who were evacuated made their way back home.
In the Florida Keys, which remain cut off from the mainland, there's high anxiety and little fuel, electricity or running water, officials said.
Irma first made landfall in the Florida Keys Sunday morning as a Category 4 hurricane, bringing 130 mph winds and a storm surge of 10 feet. It was the first Category 4 landfall in Florida since 2004. Florida Gov. Rick Scott said the storm left "devastation" in the Keys.
The Keys were under mandatory evacuation orders as Irma neared, but not everyone left.
According to the Miami Herald, Florida Director of Emergency Management Bryan Koon estimates that about 10,000 people remained in the Keys during the storm, adding it is hard to communicate with those left there.
In an interview with ABC News, Roman Gastesi, the administrator of Monroe County, which includes the Keys, said, "Unfortunately, you start to hear stories of folks that stayed in houses that shouldn't. ... We're hearing of folks that stayed in boats."
Monroe County officials said in a statement this morning that it's not yet safe to return to the Keys.
"The wind may have stopped blowing, but for most of the Florida Keys, there is no fuel, electricity, running water, or cell service. For many people, supplies are running low and anxiety is running high," the statement said.
"Once the roads are cleared, and the bridges are inspected for use, aid and relief can start to move as it is flown in," the statement said. "There are many resources staged, and ready to move into the Florida Keys to help, as soon as possible."
Officials said this afternoon that, while they understand residents' frustration, they don't anticipate a time frame of when residents will be allowed in.
After Irma left the Keys Sunday morning, it moved north, passing over Naples, which recorded a 142 mph wind gust. The city also saw nearly 12 inches of rain and a 7-foot storm surge. Farther north, wind gusts reached 94 mph in Lakeland and up to 90 mph in the Tampa Bay area.
In Miami, which saw winds up to 99 mph, resident Joe Kiener told ABC News he's endured multiple hurricanes in the Caribbean but said he had never experienced a storm as brutal as Irma.
"I've been in Miami Beach for two years, which is prone to flooding, but this completely out of the norm," Kiener said.
Kiener boarded up his house and is staying at a high-rise hotel in Miami. He said he had to move down to the lobby after his hotel room's windows took a beating from the strong winds.
"The windows started cracking, and these are massive-impact windows. They were exposed 12 hours of continuous heavy winds. At one point in time, one of them started splintering and that's when I lost my nerve and said, 'I'm leaving,'" he said. "It psychs you out -- it's just the endless hallowing and pounding of the wind."
At least seven people, including a sheriff's deputy, died of storm-related injuries in Florida as the massive hurricane barreled across the Sunshine State.
Two people were killed in Monroe County, which includes the Florida Keys. One person was found dead in a home in Shark Key. Another man was killed after he lost control of a truck that carried a generator as winds whipped at tropical-storm strength, officials said.
Two others, a sheriff's deputy and a corrections officer, died from a two-car crash in the rain in Hardee County, which is about 60 miles inland from Sarasota, officials said.
In Winter Park, near Orlando, a man was electrocuted by a downed power line Monday morning, according to the Winter Park Police Department. He was pronounced dead at the scene after investigators found him lying in the street, police said.
Another person died from carbon monoxide poisoning from improper use of a generator in Miami-Dade County, the mayor said.
Another fatality was from a car crash in Orange County in central Florida.
At least 37 people died from Irma in the Caribbean, including at least 10 in Cuba.
At least 7.7 million customers are without power in Florida, Georgia and South Carolina, including more than 6.7 million accounts in Florida alone, about 64 percent of Florida's customers.
In Miami-Dade, over 80 percent of customers lost power, the mayor said today, and a curfew is in effect until further notice.
Eric Silagy, president and CEO of Florida Power & Light, warned that "people need to be prepared for some prolonged and extended outages."
In Georgia, 748,000 customers are without power, while in South Carolina, more than 238,519 customers are without power.
About 6.5 million Floridians were ordered to evacuate as Irma neared, and some residents of Georgia and South Carolina were under evacuation orders as well.
Some chose to go to shelters, others decided to hunker down at home to ride out the storm.
One Naples resident told ABC News she was turned away from two shelters before she and her 10-year-old son were finally accepted at one.
"We have a dog and there were not that many shelters that accepted dogs," she said, adding, "We didn't want to be that far away from our home." While she and her son stay inside the shelter, her husband is hunkering down with their dog at home.
Trump approved a "major disaster" declaration in Florida on Sunday, authorizing "federal funding to flow directly to Floridians impacted by Hurricane Irma and reimburs[ing] local communities and the state government to aid in response and recovery from Hurricane Irma," state officials said.
Scott said nearly 30 states had deployed personnel and resources to help with the response to Irma.
ABC News' Max Golembo, Dan Peck, Will Gretsky, Jason Volack, Ben Gittleson and Ben Stein contributed to this report.