Florida’s governor has warned residents in the path of Hurricane Idalia to heed evacuation warnings without delay as it bears down on the US state.
Ron DeSantis said Idalia would hit the state’s Gulf coast as a Category 3 storm on Wednesday morning.
Much of Florida, including the densely populated Tampa area, is forecast to be affected by severe weather.
Idalia is projected to hit an area that Mr DeSantis said has not seen such a major hurricane since the 1800s.
High winds, up to 12in (30cm) of rain and potentially deadly storm surges as high as 15ft (4.5m) are forecast in some areas.
At 11:00 local time on Tuesday (15:00 GMT), Idalia was 275 miles (440km) south-south-west of Florida, according to the National Hurricane Center’s (NHC) most recent update.
Idalia is forecast to reach wind speeds of 125mph (201 km/h) before coming ashore north of Tampa at around 08:00 local time on Wednesday.
Mr DeSantis told a news conference at the state’s emergency operations centre that residents still have time to evacuate.
“But you got to do that now,” he said.
The governor added: “Those coastal areas there have not necessarily been through this before.”
According to the NHC, no major hurricane has tracked into Apalachee Bay in north-western Florida since 1851.
“This has the makings of an unprecedented event for this part of the state,” said the NHC in a bulletin.
Tampa International Airport closed on Tuesday, and is expected to remain shut until Thursday morning.
Florida has mobilised more than 5,500 National Guardsmen and up to 40,000 linemen are on standby to tackle power cuts.
Along evacuation routes, tolls are being waived and some 420,000 gallons of fuel is ready to be deployed at petrol stations.
Last year, Hurricane Ian made landfall in south-western Florida, wreaking more than $100bn (£79bn) in damage and killing over 100 people.