Hurricane Helene roared through Florida and into Georgia today as one of the most powerful storms to hit the U.S., with fears of deaths and widespread destruction in its wake.

At least one fatality in Florida was blamed on the hurricane so far, authorities said, as the Category 4 storm made landfall around 11:10 p.m. Eastern time (0310 GMT). Even before its arrival, the storm had caused power outages for over 1 million customers and severe flooding in several areas.

Officials feared more fatalities would be discovered today as the storm gusted in with 140 mph (225 kph) winds but weakened to 75 mph (120 kph) as it headed north into Georgia.

Helene was expected to trigger storm surges that could send 20 feet (6 meters) of seawater on land, and dump even more rain.

Authorities said it would likely be several hours before any rescue personnel could head out to help those in need.

Helene is tied as the 14th most powerful hurricane to hit anywhere in the United States since records have been kept, and is the seventh most powerful to slam into Florida, according to data from the National Hurricane Center (NHC).

In an overnight update, the NHC said Helene was weakening as it moved quickly north-northeastward near the city of Valdosta in southern Georgia. “Life-threatening storm surge, winds, and heavy rains continue,” it said.

Florida Governor Ron DeSantis said the one fatality linked to Helene was a driver whose car was struck by debris. “When we wake up tomorrow morning, the chances are there will likely have been more fatalities,” DeSantis added.

Officials pleaded with residents in the path of the storm to hunker down amid the life-threatening conditions. The storm surge was forecast to reach 15 to 20 feet (5 to 6 meters) in the Big Bend area of the Panhandle region where Helene came ashore.

“A really unsurvivable scenario is going to play out” in the coastal area, the National Hurricane Center’s director, Michael Brennan, said in a video briefing, with water capable of destroying buildings and carrying cars pushing inland.

Rain was whipping parts Florida, Georgia, South Carolina, central and western North Carolina and portions of Tennessee. Atlanta, hundreds of miles north of Florida’s Big Bend where the storm entered, was under a tropical storm warning.

In Pinellas County, which sits on a peninsula surrounded by Tampa Bay and the Gulf of Mexico, roads were already filling with water before noon. Officials warned the storm’s impact could be as severe as last year’s Hurricane Idalia, which flooded 1,500 homes in the low-lying coastal county.

Videos posted on the county’s social media site showed some swamped beachside roads and water rising over boat docks.

Airports in Tampa, Tallahassee and St. Petersburg all suspended operations on Thursday.

Helene is expected to remain a full-fledged hurricane as it rolls through the Macon, Georgia, area today, forecasters said. It could bring 12 inches (30.5 cm) of rain or more, potentially devastating the state’s cotton and pecan crops, which are in the middle of harvesting season.

“The current forecast for Hurricane Helene suggests this storm will impact every part of our state,” Georgia Governor Brian Kemp said.

After making landfall across the Florida coast, Helene is expected to move more slowly over the Tennessee Valley today and Saturday, the NHC said.

Numerous evacuations were ordered along Florida’s Gulf Coast, including Sarasota and Charlotte counties.

In Taylor County, the Sheriff’s Department wrote on social media that residents who decided not to evacuate should write their names and dates of birth on their arms in permanent ink “so that you can be identified and family notified.”

In coastal Dunedin, Florida, about 25 miles west of Tampa, state ferry boat operator Ken Wood, 58, planned to ride out the storm with his 16-year-old cat, Andy.

“We’re under orders, but I’m going to stay right here at the house,” Wood told Reuters by telephone.

Tallahassee officials expressed concern that the storm could cause unprecedented damage.

Reinsurance broker Gallagher Re said preliminary private insurance losses could reach $3 billion to $6 billion, with additional losses to federal insurance programs approaching a potential $1 billion.

Energy facilities along the U.S. Gulf Coast scaled back operations and evacuated some production sites.

The director of the Federal Emergency Management Agency, Deanne Criswell, said at a White House briefing that she would travel to Florida today to assess the damage.

Helene was expected to dump up to 15 inches (38.1 cm) of rain in some isolated spots after making landfall in Florida, causing considerable flash and urban flooding, the hurricane center said.