The most powerful hurricane ever to hit north-west Florida has flooded beach towns, submerging homes and snapping trees like twigs.
Hurricane Michael made landfall on Wednesday afternoon as a category four storm with 155mph (250km/h) winds in the state’s Panhandle region.
Two people, including a child, were killed by falling trees, officials say.
The storm left nearly 500,000 people without electricity in Florida, Alabama and Georgia, emergency services say.
Florida officials said a man was killed when he was crushed by a tree in Gadsden County.
It was later reported that a child was killed when a tree fell on a home in Seminole County, Georgia, as Hurricane Michael continued to sweep across the south-east, CBS news reports.
Michael earlier reportedly killed at least 13 people as it passed through Central America: six in Honduras, four in Nicaragua and three in El Salvador.
How powerful was Michael when it hit?
Michael was so powerful as it swept into Florida that it remained a hurricane as it moved further inland.
Its rapid intensification caught many by surprise, although the storm later weakened.
Unusually warm waters in the Gulf of Mexico turbo-charged the storm from a tropical depression on Sunday.
It was a category two hurricane by Tuesday, and a borderline category five – the highest level – on Wednesday morning.
Florida Governor Rick Scott warned of “unimaginable devastation”, saying it would be the worst storm in 100 years.
“We are in new territory,” Miami-based National Hurricane Center (NHC) meteorologist Dennis Feltgen wrote on Facebook.
“The historical record, going back to 1851, finds no category four hurricane ever hitting the Florida Panhandle.”
Reuters news agency reports that Michael is the third-most powerful storm ever to make landfall in the mainland US, after Hurricane Camille in Mississippi in 1969 and the Labor Day hurricane of 1935 in Florida.
More than 370,000 people in Florida were ordered to evacuate, but officials believe many ignored the warning.
What happened in Florida?
The hurricane made landfall near Mexico Beach, Florida, at around 14:00 (18:00 GMT) on Wednesday, according to the NHC.
The coastal city of Apalachicola reported a storm surge of nearly 8ft (2.5m).
“We are catching some hell,” Timothy Thomas, who rode out the storm with his wife in their home in Panama City Beach, Florida, told the Associated Press news agency.
As Michael continues to move, the storm has already knocked out power to a quarter of a million homes and businesses, as power lines were smashed by falling trees.
Federal Emergency Management Agency Director Brock Long said at the White House that he was especially concerned about buildings constructed before 2001, and not able to withstand such high winds.
“We just hope those structures can hold up,” President Donald Trump responded. “And if not, that they’re not in those structures.”
States of emergency have been declared in all or parts of Florida, Alabama, Georgia and North Carolina.
The National Weather Service (NWS) had issued a dramatic appeal for the people of the Florida state capital, Tallahassee, to heed warnings and leave their homes.
Schools and state offices in the area are to remain shut this week.
Florida has activated 3,500 National Guard troops.
What happens next?
In the early hours of Thursday, Hurricane Michael’s maximum sustained winds decreased to 75mph, the NHC said in a bulletin.
“Michael will steadily weaken as it crosses the south-eastern United States through Thursday night, becoming a tropical storm by Thursday morning.
“Michael is forecast to re-strengthen some Thursday night and Friday when it moves off the east coast of the United States and becomes a post-tropical cyclone on Friday,” the NHC added.
More than 300 miles of coastline remained under threat, the NWS said.
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