CRAWFORDVILLE, Florida — Hurricane Helene weakened to a tropical storm over Georgia with maximum sustained winds of 70 mph early Friday, the National Hurricane Center said.

Helene is weakening while moving farther inland over Georgia. The storm was about 40 miles east of Macon and about 100 miles southeast of Atlanta, moving north at 30 mph at 5 a.m., the center at Miami reported.

The storm made landfall in northwestern Florida as a Category 4 storm as forecasters warned the enormous system could create a “nightmare” storm surge and bring dangerous winds and rain across much of the southeast. There were at least three storm-related deaths.

The hurricane center said Helene roared ashore around 11:10 p.m. Thursday near the mouth of the Aucilla River in the Big Bend area of Florida’s Gulf Coast. It had maximum sustained winds estimated at 140 mph. That location was only about 20 miles northwest of where Hurricane Idalia came ashore last year at nearly the same ferocity and caused widespread damage.

The hurricane’s eye passed near Valdosta, Georgia, as the storm churned rapidly north into Georgia Thursday night. The National Hurricane Center issued an extreme wind warning for the area, meaning possible hurricane-force winds exceeding 115 mph.

At a hotel in the city of 55,000 near the Florida line, dozens of people huddled in the darkened lobby after midnight Friday as winds whistled and howled outside. Electricity was out, with hall emergency lights, flashlights and cellphones providing the only illumination. Water dripped from light fixtures in the lobby dining area and roof debris fell to the ground outside.

Fermin Herrera, 20, his wife and their 2-month-old daughter left their room on the top floor of the hotel, where they took shelter because they were concerned about trees falling on their Valdosta home.

“We heard some rumbling,” said Mr. Herrera, cradling the sleeping baby in a downstairs hallway. “We didn’t see anything at first. After a while the intensity picked up. It looked like a gutter that was banging against our window. So we made a decision to leave.”

Helene is the third storm to strike the city in just over a year. Tropical Storm Debby blacked out power to thousands in August, while Hurricane Idalia damaged an estimated 1,000 homes at Valdosta and surrounding Lowndes County a year ago.

“I feel like a lot of us know what to do now,” Mr. Herrera said. “We’ve seen some storms and grown some thicker skins.”

Helene prompted hurricane and flash flood warnings extending far beyond the coast up into northern Georgia and western North Carolina. More than 1.2 million homes and businesses were without power in Florida, more than 190,000 in Georgia, and more than 30,000 in the Carolinas, according to the tracking site poweroutage.us. The governors of those states and Alabama and Virginia all declared emergencies.

One person was killed in Florida when a sign fell on their car and two people were reported killed in a possible tornado in south Georgia as the storm approached.

“When Floridians wake up tomorrow morning, we’re going to be waking up to a state where very likely there’s been additional loss of life and certainly there’s going to be loss of property,” Governor DeSantis said at a news conference Thursday night.

Helene was moving rapidly inland after making landfall, with the center of the storm set to race from southern to northern Georgia through early Friday morning.

The risk of tornadoes also would continue overnight and into the morning across north and central Florida, Georgia, South Carolina and southern North Carolina, forecasters said. Later Friday, there would be the risk of tornadoes in Virginia.