Hurricane Michael weakens to Category 1 over Georgia after slamming Florida

• For Thursday coverage of Michael, click here.

Hurricane Michael slammed into the Florida Panhandle with terrifying winds of 250 km/h Wednesday, splintering homes and submerging neighbourhoods before continuing its destructive march inland across the southeast. It was the most powerful hurricane to hit the continental U.S. in nearly 50 years and at least one death was reported during its passage.

Supercharged by abnormally warm waters of the Gulf of Mexico, the Category 4 storm crashed ashore in the early afternoon near Mexico Beach, a tourist town midway along the Panhandle, a 320-kilometre stretch of white-sand beach resorts, fishing towns and military bases. After it ravaged the Panhandle, Michael entered south Georgia as a Category 3 hurricane with winds of 185 km/h the most powerful in recorded history for that part of the neighbouring state.

As Michael crossed Georgia, it weakened to a Category 1 with sustained winds of 145 km/h and a continued risk of heavy rain and flooding.

The National Weather Service has also issued multiple tornado warnings in Georgia, with local media reporting three tornadoes had touched down.

In north Florida, Michael battered the shoreline with sideways rain, powerful gusts and crashing waves, swamping streets and docks, flattening trees, stripped away leaves, shredding awnings and peeling away shingles. It also set off transformer explosions and knocked out power to more than 192,000 homes and businesses, the governor said.

A man was killed in Greenboro, Fla., after a tree crashed through is home and trapped him, the local sheriff's spokesperson said.

Damage in Panama City was extensive, with broken and uprooted trees and power lines down nearly everywhere. Roofs were peeled off and homes split open by fallen trees. Twisted street signs lay on the ground. Residents emerged in the early evening to assess damage when rains stopped, though skies were still overcast and windy.

Vance Beu, 29, was staying with his mother at her apartment, Spring Gate Apartments, a small complex of single-storey wood-frame apartment buildings. A pine tree punched a hole in their roof and he said the roar of the storm sounded like a jet engine as the winds accelerated. Their ears even popped as the barometric pressure dropped.

"It was terrifying, honestly. There was a lot of noise. We thought the windows were going to break at any time. We had the inside windows kind of barricaded in with mattresses," Beu said.

Kaylee O'Brien was crying as she sorted through the remains of the apartment she shared with three roommates at Whispering Pines apartments, where the smell of broken pine trees was thick in the air. Four pine trees had crashed through the roof of her apartment, nearly hitting two people. She was missing her one-year-old Siamese cat, Molly.

"We haven't seen her since the tree hit the den. She's my baby."

In Apalachicola, Sally Crown rode out the storm in her house. The worst damage she thought was in her yard. Multiple trees were down. But after the storm passed, she drove to check on the cafe she manages and saw the scope of the destruction.

"It's absolutely horrendous. Catastrophic," Crown said. "There's flooding. Boats on the highway. A house on the highway. Houses that have been there forever are just shattered."

Gov. Rick Scott announced soon after the powerful eye had swept inland that "aggressive" search and rescue efforts were just beginning and urged people to stay off debris-littered roads.

"If you and your family made it through the storm safely, the worst thing you could do now is act foolishly," he said.

Michael was a meteorological brute that 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 was the most powerful hurricane on record to hit the Panhandle.

A water-level station in Apalachicola, close to where Michael came ashore, reported a surge of nearly 2.5 metres.

A Red Cross official says some 320,000 people along Florida's Gold Coast chose to ride out the storm.

Emergency managers say they don't know how many left the area, but there were about 6,000 people in 80 shelters in five states, including nearly 1,200 who are still in shelters following Hurricane Florence. Evacuation orders had been sent to 325,000 people.

Based on its internal barometric pressure, Michael was the most powerful hurricane to blow ashore on the U.S. mainland since Camille in 1969. Based on wind speed, it was the fourth-strongest, behind Andrew in 1992, Camille, and the biggest one of all, an unnamed 1935 Labour Day storm that had winds 296 km/h.

It appeared to be so powerful that it would remain a hurricane as it moved into south Georgia early Thursday. Forecasters said it would unleash damaging wind and rain all the way into the Carolinas, which are still recovering from Hurricane Florence's epic flooding.

'We are in new territory'

Meteorologists watched satellite imagery in complete awe as the storm intensified.

"We are in new territory," NHCmeteorologist Dennis Feltgen wrote on Facebook. "The historical record, going back to 1851, finds no Category 4 hurricane ever hitting the Florida panhandle."

The storm is likely to fire up the debate over global warming.

Scientists say global warming is responsible for more intense and more frequent extreme weather, such as storms, droughts, floods and fires. But without extensive study, they cannot directly link a single weather event to the changing climate.

With files from CBC News