Weather agencies warn the storm is expected to dump 6 to 12 inches of rain in Florida and 20 to 30 inches in coastal Georgia and South Carolina.
At least four people have been killed after Hurricane Debby made landfall in the Big Bend region of Florida’s Gulf Coast, leaving residents coping with flooding, power outages and treacherous roads.
The weather system strengthened into a Category One hurricane late on Sunday and came ashore near Steinhatchee on Monday morning, said the National Hurricane Center (NHC).
It is now expected to move slowly across the state, packing 80mph winds and dumping as much as 30in (76cm) of rain as it moves north.
The fourth named storm of the season is also forecast to soak Georgia and South Carolina in the days ahead.
Authorities said that the dead included a 13-year-old boy who was killed when a tree fell onto his mobile home in the town of Levy County, located near Gainesville.
In a separate incident, in Hillsborough County – part of the Tampa metropolitan area – the driver of an 18-wheel vehicle lost control and veered into a canal during the storm, authorities said.
The driver was later found dead.
In Dixie County, just west of Gainesville, officials reported that a woman and a 12-year-old were killed when their car crashed on Sunday night.
Florida Governor Ron DeSantis later said that reports indicated the vehicle had hydroplaned during the storm before crashing.
The slow-moving nature of the storm could mean historic amounts of rainfall, Jamie Rhome, the deputy director of the hurricane center, said as the storm struck land.
“You’re talking about catastrophic flooding.”
Already the storm’s strong winds are impacting Florida residents – some 242,000 homes and businesses are without power in the state, according to PowerOutage.com.
Debby is expected to slow down dramatically on its journey across Florida as the steering flow of winds high in the atmosphere essentially collapses.
This will leave the hurricane drifting slowly out over the Atlantic as a tropical storm where it will churn over the ocean, relentlessly throwing bands of rain into south-east Georgia and the Carolinas on Tuesday and Wednesday, before moving inland over South Carolina on Thursday.
Historic rainfall is likely to lead to areas of catastrophic flooding, exacerbated by a storm surge along the coast which could leave water trapped in river systems, unable to drain into the ocean.
Ahead of the storm making landfall, Mr DeSantis declared a state of emergency for 61 of Florida’s 67 counties. He also said utility crews from in and out of state are ready to help restore power after the storm.
Mr DeSantis is not the only one preparing, residents across the state are getting ready for the worst.
Spyridon Aibejeris told USA Today repairs on his Keaton Beach home had just wrapped up two weeks ago from Hurricane Idalia, a category three storm that made landfall last summer.
“Man, I’ve done this so many times,” Mr Aibejeris said. “You just go back and see what you’ve got to do.”
“I hope I don’t have to go back to that again,” he added.
Forecasters predicted this hurricane season, which runs from 1 June to 30 November, would be a busy one.
The National Oceanic and Atmospheric Administration (NOAA) issued its most startling warning to date about the current season. Forecasters said there could be up to 25 named storms in 2024.
Between eight and 13 of those storms could develop into hurricanes, the NOAA said.
Hurricane Debby marks the fourth named storm of the year after Tropical Storm Alberto, Hurricane Beryl and Tropical Storm Chris.
It is thought that climate change may be making slow-moving hurricanes like this more likely.
As the world heats unevenly, this causes changes in the atmospheric circulations that
