HURRICANE Michael has been upgraded to a Category 4 storm with residents in Florida warned of deadly flash floods and 225 km/h winds.

The Sun reports the National Hurricane Centre described it as “extremely dangerous” as it made landfall about 1:40pm local time (4:40am AEDT) with the Weather Channel calling it the strongest hurricane to hit the region since records began.

It comes as US President Donald Trump said he would visit the area on Sunday or Monday, after the storm had passed.

The “monstrous” storm is expected to cause major damage.

Michael brought heavy rains to Cuba on Monday on its path to Florida after leaving at least 13 people dead in Central America over the weekend.

Six people died in Honduras, four in Nicaragua and three in El Salvador, the Associated Press reports.

Hurricane Michael is the strongest hurricane to ever hit the Florida Panhandle since records began in 1851, according to Weather.com.

Only three major hurricanes that were Category 3 or higher have struck the Panhandle since 1950. They include Eloise in 1975, Opal in 1995 and Dennis in 2005.

The area is a 322km stretch lying between Alabama on the north west, Georgia on the north east and the Gulf of Mexico to the south.

The National Weather Service in Tallahassee, Florida, warned: “A potentially catastrophic event is developing. Locations may be uninhabitable for weeks or months.”

Florida Governor Rick Scott tweeted: “The time to evacuate has come and gone … SEEK REFUGE IMMEDIATELY.”

Senator Bill Nelson said a “wall of water” could cause major destruction along vulnerable areas of the Panhandle.

“Don’t think that you can ride this out if you’re in a low-lying area,” he said on CNN.

Escambia County Sheriff David Morgan bluntly advised those residents choosing to stay that rescuers won’t be able to reach them.

“If you decide to stay in your home and a tree falls on your house or the storm surge catches you and you’re now calling for help, there’s no one that can respond to help you,” he said.

Earlier, Franklin County Sheriff A.J. Smith said his deputies had gone door to door in some places urging people to evacuate.

“We have done everything we can as far as getting the word out,” he said.

Weather experts sent out similar grim warnings with National Hurricane Centre Director Ken Graham saying: “If they tell you to leave, you have to leave.”

Thousands were warned to evacuate along Florida’s coast, where schools and state offices are to remain shut this week.

Jason McDonald, of Panama City was driving with his wife and two young children, aged five and seven, to North Alabama.

He said: “We don’t know if it’s going to wipe out our house or not. We want to get them out of the way.”

Others have decided to stay put despite the “life-threatening” storm surge because of how much it costs to evacuate.

Aja Kemp said she spent more than $800 last year when her and family evacuated for Hurricane Irma.

She said: “I just can’t bring myself to spend that much money.

“We’ve got supplies to last us a week. Plenty of water. I made sure we’ve got clean clothes. We got everything tied down.”

One county in Florida cannot open their shelters because they can only withstand a Category 2 hurricane.

Shelters in Wakulla County is unable to provide protection for the residents that have been ordered to leave.

Residents were being taken by van to the neighbouring Leon County.

More than 482 kilometres of coastline are currently under threat, the National Weather Service has said.

Some regions of the US may see 30cm of rain, and storm surges of up to 3.6m.