Search and rescue teams are trying to help survivors after Hurricane Michael wreaked "unimaginable destruction" on parts of Florida.
Thousands of houses were destroyed by the third-most powerful hurricane on record to hit the continental US.
At least two deaths were blamed on Michael, and though weakened into a tropical storm, it continued to bring heavy rain and blustery winds to the south east as it pushed inland.
A man was killed by a tree falling on a home in the Panhandle region as winds reached 155mph in the Category 4 storm.
An 11-year-old girl died after a tree came down on a house in south-west Georgia.
Supercharged by abnormally warm waters in the Gulf of Mexico, Michael destroyed homes and caused flooding.
It has now been downgraded to a tropical storm as it moves over Georgia, but it still bringing heavy rains, blustery winds and the possibility of spin-off tornadoes.
Search and rescue crews are expected to escalate efforts to reach the hardest-hit areas and check for anyone trapped or injured in the storm debris.
Damage in Panama City, near where Michael came ashore on Wednesday afternoon, was so extensive that broken and uprooted trees and downed power lines lay nearly everywhere.
Roofs were peeled away, sent airborne, and homes were split open by fallen trees, while more than 380,000 homes and businesses were without power at the height of the storm.
Vance Beu, 29, was staying with his mother at her home, said a tree punched a hole in their roof. He said the wind sounded like a jet engine.
“It was terrifying, honestly," Mr Beu said. "There was a lot of noise. We thought the windows were going to break at any time."
Sally Crown rode out Michael on the Florida Panhandle, emerging to find the cafe she manages devastated.
“It’s absolutely horrendous. Catastrophic,” Ms Crown said. “There’s flooding. Boats on the highway. A house on the highway. Houses that have been there forever are just shattered.”
Governor Rick Scott announced that thousands of law enforcement officers, utility crews and search and rescue teams would go into recovery mode.
Michael sprang quickly from a weekend tropical depression, going from a Category 2 on Tuesday to a Category 4 by the time it came ashore.
It forced more than 375,000 people up and down the Gulf Coast to evacuate as it gained strength quickly while crossing the eastern Gulf of Mexico toward north Florida.
Based on its internal barometric pressure, Michael was the third most powerful hurricane to hit the US mainland, behind the unnamed Labour Day storm of 1935 and Camille in 1969. Based on wind speed, it was the fourth-strongest, behind the Labour Day storm (184 mph), Camille and Andrew in 1992.
“We are in new territory,” National Hurricane Centre Meteorologist Dennis Feltgen wrote on Facebook. “The historical record, going back to 1851, finds no Category 4 hurricane ever hitting the Florida Panhandle.”