By Julia Harte and Rachel Nostrant
(Reuters) -Here are the most important things to know about the projected impact of Hurricane Idalia, which was weakening but still raging as it moved from Florida to Georgia on Wednesday, leaving a swath of destruction that will take time to assess.
WHAT IS IDALIA'S PATH?
As of 2 p.m. EDT (1800 GMT), Idalia was packing maximum sustained winds of 75 mph (120.7 kph) as it whirled through southern Georgia toward Savannah, the National Hurricane Center (NHC) said in its latest advisory. The NHC issued a hurricane warning for areas between Altamaha Sound, Georgia and Edisto Beach, South Carolina.
Georgia Governor Brian Kemp said in a press conference on Wednesday afternoon the storm was expected to pass through Georgia and into South Carolina between 8 p.m. and 10 p.m. EDT.
Idalia's eye had crossed Florida's coastline over the Big Bend region, where the state's northern panhandle meets the Gulf side of the Florida peninsula, and was headed northeast toward Charleston, South Carolina.
The NHC forecast Idalia would become a tropical storm while moving over the coasts of northeastern South Carolina and North Carolina on Wednesday night and early on Thursday.
Florida moved from a hurricane advisory to a tropical storm advisory by mid-Wednesday afternoon, according to the latest NHC update.
Idalia was eventually expected to spin out over the Atlantic Ocean.
DEADLY RAINS, SURGING SEAS
Flash and river floods are forecasted throughout Georgia and the Carolinas through Thursday, according to the NHC.
Two motorists died in separate rain-related crashes on Wednesday morning, according to the Florida Highway Patrol.
More than 75 people have been rescued from flood waters in St. Petersburg, the city said on social media platform X, posting a video of two rescue workers in a small boat traveling through a flooded neighborhood in heavy rains.
The deadliest threat Idalia poses is a surging wall of seawater that could flood low-lying areas along Florida's coast, according to authorities.
Surge warnings were posted for hundreds of miles of shoreline, from Sarasota to the western end of Apalachicola Bay in Florida and from St. Catherine's Sound Georgia to South Santee River, South Carolina. Surges could rise as high as 16 feet (5 meters) in Florida and 8 feet in Georgia, according to the NHC.
"Storm surges" occur when high winds and atmospheric pressure from an oncoming hurricane force ocean water onto land. The resulting floodwaters may take a couple of days to subside.
A "king tide" - the highest type of high tide, caused by the extra gravitational pull that occurs when the sun and moon align with Earth - on Wednesday will likely exacerbate the surges from Idalia.
Camden County in Georgia, where the chairman signed a state of emergency, issued an evacuation order, specifically for the residents of Cumberland Island and Little Cumberland Island. No other evacuation orders had been listed in Georgia as of 2 p.m. EST.
The Florida emergency management agency listed 28 counties with evacuation orders, 16 as mandatory for certain residents, especially those living in coastal and flood-prone areas or in mobile homes, recreational vehicles or structurally unsound housing.
Over 275,000 homes and businesses were without power in Florida as of midday, Poweroutage.us reported. More than 64,000 in Georgia were also without power.
Some 30,000 to 40,000 electricity workers had been placed on standby to help restore power quickly after the hurricane passes.
Deanne Criswell, the U.S. Federal Emergency Management Agency's administrator, said on Wednesday morning that more than 1,000 personnel from FEMA's rapid assessment teams were ready to hit the ground to assess storm damage once Idalia passes.
President Joe Biden called the governors of Florida, Georgia, South and North Carolina promising his administration's full support.
Prior to landfall, Biden had directed the federal government to pre-position personnel and resources to immediately support the states' response and recovery efforts.
(Reporting by Julia Harte and Rachel Nostrant; Editing by Donna Bryson, Andy Sullivan, Cynthia Osterman, Marguerita Choy and Sandra Maler)