FOG BLOG WEATHER LOG: HURRICANE IAN MAKES LANDFALL NEAR FT. MYERS FL. AS POWERFUL CAT 4 STORM:

Hurricane Ian makes landfall in southwestern Florida as catastrophic Category 4 storm Slow-moving storm is packing sustained winds of up to 241 km/h Hurricane Ian made landfall Wednesday in southwest Florida as one of the most powerful storms ever recorded in the U.S., swamping city streets with water and smashing trees along the coast.

The hurricane's centre struck Wednesday afternoon near Cayo Costa, a protected barrier island just west of heavily populated Fort Myers. The massive storm was expected to trigger flooding across a wide area of Florida as it crawls northeastward across the peninsula.

About 2.5 million people were ordered to evacuate southwest Florida before the storm hit the coast with maximum sustained winds of 241 km/h. It was heading inland, where it was expected to weaken, moving at about 14 km/h, but residents in central Florida could still experience hurricane-force winds.

Before making its way through the Gulf of Mexico to Florida, Hurricane Ian tore into western Cuba as a major hurricane Tuesday, killing two people and bringing down the country's electrical grid. Catastrophic storm surges could push 3.6 to 5.5 metres of water across more than 400 kilometres of coastline, from Bonita Beach to Englewood, forecasters warned.

"This is going to be a nasty nasty day, two days," Florida Gov. Ron DeSantis said, stressing that people in Ian's path along the coast should rush to the safest possible shelter and stay there.

Off the coast on Sanibel Island, just south of where Ian made landfall, traffic cameras hours earlier showed swirling water that flooded streets and was halfway up mailbox posts. Seawater rushed out of Tampa Bay as the storm approached, leaving parts of the muddy bottom exposed, and waves crashed over the end of a wooden pier at Naples.

"It's going to get a lot worse very quickly," DeSantis said. "So please hunker down."

Jackson Boone left his home near the coast and hunkered down at his law office in Venice with employees and their pets. Boone at one point opened a door to howling wind and rain flying sideways.

"We're seeing tree damage, horizontal rain, very high wind," Boone said by telephone. "We have a 50-plus-year-old oak tree that has toppled over." In Naples, the first floor of a fire station was inundated with about one metre of water and firefighters worked to salvage gear from a firetruck stuck outside the garage in even deeper water, a video posted by the Naples Fire Department showed.

Naples is in Collier County, where the sheriff's department reported on Facebook that it was getting "a significant number of calls of people trapped by water in their homes" and that it would prioritize reaching people "reporting life-threatening medical emergencies in deep water."

Ian's windspeed at landfall tied it for the fifth-strongest hurricane to strike the U.S., along with several other storms. Among them was Hurricane Charley, which hit almost the same spot on Florida's coast in August 2004, killing 10 people and inflicting $14 billion US in damage.