Hurricane Ian made landfall on the west coast of the US state of Florida.

The center of the four out of five hurricane hit the coast near the city of Cape Coral, the US hurricane center announced on Wednesday.

It is therefore an "extremely dangerous hurricane" that is likely to lead to meter-high storm surges, flooding and heavy rainfall.

The authorities warned that serious damage to infrastructure, communication lines and widespread and sustained power outages are to be expected.

Evacuation instructions applied to 2.5 million people in the region.

The first photos and videos on social media already showed severe flooding in the cities of Fort Myers Beach, Cape Coral and Naples, some of which were several meters high.

Around a million homes in Florida are already without power, according to the Poweroutage website.

According to US information, a boat carrying migrants from Cuba had sunk off the coast of Florida earlier that evening.

The coast guard was looking for 23 people on Wednesday, as announced on Twitter.

Four migrants had previously reached America's Stock Island off Key West by swimming from the boat in "unfriendly" weather, sources said.

Overland, the storm system should soon lose strength, the hurricane center said.

"Ian" could still have destructive hurricane strength on Thursday's arrival on the east coast of the state, forecasters warned.

The hurricane had increased significantly in strength over the Gulf of Mexico on its way towards Florida and, with wind speeds of around 240 kilometers per hour, was just below the threshold for the highest hurricane category.

Florida's governor Ron DeSantis had previously prepared the population in his state for severe damage from the approaching hurricane "Ian".

"This is a big, strong storm," DeSantis said Wednesday morning in the Florida capital, Tallahassee.

"He's going to do a lot of damage," he warned.

The Republican politician predicted that the next day or two would be "very ugly" before the hurricane passed Florida.

"It's going to be a tough track."

"Ian" made landfall in Cuba on Tuesday as a category three of five hurricane.

In the province of Pinar del Río, which was particularly hard hit, two people died after their houses collapsed, the Cuban government said.

In the state with a good eleven million inhabitants, the electricity failed nationwide.