HURRICANE Irma spun up funnel clouds and at least one tornado as it approached the US, leading to warnings for parts of South Florida.

The National Weather Service in Miami posted on Twitter Saturday evening (local time) that a tornado had touched the ground in the Fort Lauderdale suburb of Oakland Park. It wasn’t immediately clear how much damage was caused.

Tornado warnings have been issued for Fort Lauderdale, Coral Springs, Pompano Beach and Sunrise in Broward County, as well as parts of nearby Palm Beach and Hendry Counties.

A local journalist captured footage of a tornado approaching land at Fort Lauderdale.

#BREAKING tornado coming ashore then breaks up as it moves off the ocean onto land here in #FortLauderdale @CBSMiami pic.twitter.com/Brv3ETfGbu — Mike LaCrosse (@MikeLaCrosseWBZ) September 9, 2017

Hurricance Irma was upgraded to a Category 4 as the storm’s centre edged closer to Florida Keys.

The former Category 5 storm was downgraded to a Category 3 on Saturday but has intensified as it continues on its trajectory.

The US National Hurricane Center said Irma was expected to weaken again but would remain a powerful storm as it moved through the Florida Keys and near the state’s west coast.

As of 5am EDT Sunday, the hurricane was centered about 65 kilometres south-southeast of Key West, Florida.

Florida Governor Rick Scott tweeted that a life-threatening storm surge was now impacting parts of the Florida Keys, and would reach south-west Florida in a few hours.

Starting to see some Miami Beach street flooding -- this is 30th Street near Collins. @wsvn #HurricaneIrma pic.twitter.com/B4N6EgC6gj — Brian Entin (@BrianEntin) September 10, 2017

The National Weather Service said the first hurricane-force wind gust has been recorded in the Florida Keys as Irma inches closer to the state.

The eye of the storm is expected to hit the Florida Keys between 7-8am EDT (9-10pm Sunday AEDT) before moving near or over the southwestern coast of the Florida Peninsula. Irma is expected to then move inland over the Florida panhandle and southwestern Georgia on Monday afternoon.

It may now potentially spare Tampa as well Miami the catastrophic head-on blow forecasters had been warning about for days.

But St Petersburg could instead get a direct hit, rather than its more populous twin across Tampa Bay. Neither city has suffered a major hurricane in nearly a century.

The catastrophic storm has already bent palm trees and spit rain across the state’s south, knocking out power to more than 170,000 homes and businesses.

Florida Power and Light said on its website that more than half of those outages were in the Miami-Dade area, where about 600,000 people have been ordered to evacuate.

The company has said it expects millions of people to lose power, with some areas experiences prolonged outages.

The company said it had assembled the largest pre-storm workforce in US history, with more than 16,000 people ready to respond.

Across Florida six million people have been ordered to evacuate their homes, leaving residents dreading what they might return to.

“Tonight, I’m sweating. Tonight I’m scared to death,” said 60-year-old Carol Walterson Stroud, who sought refuge in a senior center in Florida’s southernmost city with her husband, granddaughter and dog Saturday night.

The streets emptied and shops were boarded up before the wind started to howl.

The first hurricane-force wind gusts have been recorded in the Florida Keys and at least one tornado has been whipped up by Irma’s force.

Florida Governor Rick Scott earlier announced “the storm is here” as the outer bands of Hurricane Irma start to lash the state’s southern tip and warned “our state has never seen anything like it”.

Governor Scott said time is fast running out for 6.3 million Americans ordered to flee Hurricane Irma and warned them to take shelter immediately or “you will not survive”.

He says the massive storm is likely to cause widespread damage and that people should stay away until they are told by local officials that they can return.

Florida resident Ashley Winnie, who lives in the northern city of Jacksonville, told news.com.au she feared she may not have a home to go back to.

“The storm hits Florida starting on Sunday, so folks really need to leave now. Other northern counties in Florida are issuing evacuations today. Leaving sucks. Trying to pack everything you need (important documents, any personal items, etc.) in a short amount of time isn’t fun,” she said.

“No one wants to leave their home. I dread going back to Florida and taking in the damage. I hope I have a home to go back to.”

Ms Winnie said she wanted to stay in her home to ride out the storm “and say I lived through Irma”.

“Then I actually looked at my house and realised a tree could fall on my bedroom while I slept and I would be helpless,” she said.

Governor Scott told residents: “If you have been ordered to evacuate, leave now — not tonight, not in an hour, now”.

“This is a deadly storm and our state has never seen anything like it.”

The warning came as Irma shifted its deadly course toward Florida’s west coast.

President Donald Trump held a cabinet meeting to discuss Hurricane Irma at Camp David presidential retreat on Saturday afternoon. President Trump posted a brief video from the meeting to Twitter, sending his prayers to the people who have already been affected by the hurricane and speaking about the emergency measures that have been put in place.

“All of America grieves for those who have already lost their lives, we have had many lives lost already from Hurricane Irma and it hasn’t even hit shore,” he said as he addressed the cabinet.

He urged residents in the impending storm’s path to “get out of its way”.

“This is a storm of enormous destructive power and I ask everyone in the storm path to heed all instructions,” he said.

“Property is replaceable but lives are not and safety has to come first.”

This is a storm of enormous destructive power, and I ask everyone in the storm’s path to heed ALL instructions from government officials. pic.twitter.com/nJfM2Sdme1 — Donald J. Trump (@realDonaldTrump) 9 September 2017

Early forecasts had Hurricane Irma striking Florida’s south east capital of Miami hardest, but overnight the storm moved slightly west and is now pummelling Florida’s west coast, with Tampa and Fort Meyer bearing the brunt before Irma powers inland.

Tampa’s Mayor Bob Buckhorn said overnight: “It is not looking good for us.”

Florida Governor Scott imposed a curfew of between 7pm and 7am in Miami to stop opportunistic looters taking advantage of abandoned homes and shops.

On Saturday, many businesses in Orlando were closed, with owners working to put up plywood and storm shutters. Miami consultant Nina Cohen said she didn’t hesitate to evacuate her Coral Cables home when Irma started churning. She and thousands of other Miami residents had headed north to pack Orlando’s hotels. “I haven’t seen anything like this, and I have lived in Florida 40 years,” said Ms Cohen, who had to rebuild her home after Hurricane Andrew in 1992.

“We all went through Andrew, lost homes, and this is looking worse than Andrew ever did.”

Ms Cohen’s friend’s Shirley Crane and her husband Bo travelled north with her and yesterday said they hoped it wasn’t a decision they would regret. “It’s hard to know the right thing to do, but we didn’t feel safe in Miami,” Mrs Crane said.

“But ask us next Wednesday if it was the right call — then we’ll know for sure.”

Irma hit Cuba late on Friday as a Category 5 hurricane, its violent gusts destroying the instrument used to measure wind strength, Cuba’s meteorological agency reported.

At least 25 people were killed even before Irma hit Cuba, leaving entire islands in ruins.

Storm surge flooding can happen fast -- very fast. This @ncargis animation shows just how much flooding can occur in only 12 minutes. #Irma pic.twitter.com/IJRFNdvRKj — NCAR & UCAR Science (@AtmosNews) September 8, 2017

And a new danger lays on the horizon to the east: Hurricane Jose, a Category 4 storm with 150mph (241km/h) winds that could punish some of the devastated areas all over again this weekend.

Also, the governor of the Mexican Gulf coast state of Veracruz reported two deaths related to the arrival of Hurricane Katia, which has since been downgraded to a tropical storm.

Governor Miguel Angel Yunes says the two died in a mudslide in a country still reeling from the strongest earthquake to hit Mexico in a century, which killed at least 61 people.

In one of the largest mass evacuations ever undertaken, more than 6.3 million Americans have been ordered from their homes, with police yesterday driving door-to-door and warning over loudspeaker that anyone who stayed was “on their own”.

Irma will bring sustained wind gusts of more than (157mph) 252km/h, which can easily destroy buildings, rip up roads, topple power lines and cripple infrastructure.

Widespread flooding is also expected, but not at the same levels with which Hurricane Harvey tormented Texas last month.

AUSSIES CAUGHT UP IN STORM

Australian cafe owner Marlies Laaper yesterday said she and her husband Uri Aminov had missed out on evacuating because their home on Florida’s west coast at Cape Coral was initially not in the forecast impact zone.

“We weren’t planning to evacuate because there hasn’t been an order and the hurricane was going to hit the east coast,” she said.

“Now it’s probably too late for us to leave.”

Ms Laaper, who has lived in Florida for ten years, said she spent yesterday preparing storm shutters and floodproofing her home and business, Café You.

“I am just too busy to be scared right now,” she said.

“But I am sure when we are sitting at home tomorrow with a hurricane battering down on us I will probably get a little nervous.”

RESIDENTS STOCK UP ON FOOD, PETROL, WATER

Fuel is scarce as millions clogged highways headed north. Those who didn’t try to flee by car filled shelters, set up in schools, churches, even speedways.

Supermarkets across the state have been bled dry of non-perishable food and water. At Walmart in Orlando yesterday, there was no water available and entire shelves of tinned food were stripped — leaving only pickled clams and lumpfish caviar behind.

“It’s been crazy in here the past couple days,” said cashier Andria Franklin, a lifelong Orlando resident.

“Usually people here don’t pay much attention to hurricanes because they happen a lot. But people were scared by what happened in Houston and so they seem to be taking this one a lot more seriously.”

The theme park capital of Orlando in central Florida is slightly inland so isn’t normally too badly battered in hurricane season as the storms lose strength as they travel over land. Yesterday several of the city’s famous theme parks closed down and the spires of the Disney

castle were taken down for protection.

At twice the size of the entire state, Irma is so big that Governor Rick Scott said yesterday “all Floridians should be prepared to evacuate”.

“It’s not a question of if Florida’s going to be impacted, it’s a question of how bad Florida’s going to be impacted and where the storm ends up,” said William Long of the Federal Emergency Management Agency (FEMA).

The FEMA boss said anyone who thought they had lived through other devastating storms such as Andrew in 1992 (one of only two hurricanes to make landfall as a category 5 after Camille in 1969) didn’t understand Irma’s potential.

Mr Long said Irma was “a threat that is going to devastate the United States, either Florida or some of the southeastern states,” and he warned residents in states from Alabama to North Carolina to be prepared.