MIAMI -- The ferocious Hurricane Irma caused multiple deaths and left thousands homeless on islands across the northern Caribbean as it cut a devastating path that could lead to a catastrophic strike on Florida.

Irma weakened only slightly Thursday from its peak, remaining a powerful Category 5 storm with winds of 175 mph.

Here's a look at what to expect as Irma approaches:

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What's in the forecast for Irma?

Irma appears increasingly likely to rip into heavily populated South Florida early Sunday. Gov. Rick Scott has declared a state of emergency, and mandatory evacuation orders are in place for parts of the Miami metro area and the Florida Keys.

"We cannot save you once the storm hits," Scott warned, urging residents to heed local evacuation orders.

Parts of South Florida were placed under a hurricane watch Thursday.

Forecasters said Irma could rake the entire Atlantic coast of Florida and rage on into Georgia and South Carolina.

Georgia's governor has ordered a mandatory evacuation starting Saturday from the state's Atlantic coast ahead of Hurricane Irma. That includes the city of Savannah.

What has Hurricane Irma done so far?

French, British and Dutch rescuers struggled to rush aid to a string of Caribbean islands Thursday after Hurricane Irma left at least six dead and thousands homeless.

Nearly every building on the island of Barbuda was damaged when the eye of the storm passed early Wednesday. That left about 60 percent of the island's roughly 1,400 people homeless, Antigua and Barbuda Prime Minister Gaston Browne told The Associated Press.

About a million people were without power in Puerto Rico after Irma sideswiped the island, but there were no immediate reports of large-scale casualties.

Florida evacuation traffic jams

After parts of southern Florida were placed under an evacuation order, some drivers faced traffic jams and fuel shortages as they tried to head north to safety. At least 31,000 people fled the Florida Keys, which could begin seeing wind and rain from Irma as early as Friday night, Gov. Rick Scott said.

Motorists head north, Wednesday, Sept. 6, 2017, in Islamorada, Fla. Alan Diaz / AP

The Republican governor acknowledged that traffic jams and gas shortages were "frustrating," and said federal authorities and other states were helping to move more fuel into the state.

"We are aggressively working around the clock to bring more fuel to Florida gas stations," Scott said Thursday, CBS Miami reported. "I have directed state police to escort fuel trucks to gas stations along evacuation routes. For gas stations in evacuation zones: we need you to stay open as long as possible so people can get out. We will arrange police escorts for your employees so they can get out safely."

One flight into the storm

A daring Delta Air Lines crew braved Hurricane Irma's wind and rain to fly in and out of Puerto Rico to pick up travelers.

The flight-tracking website FlightRadar24 shared a radar image showing the plane heading into San Juan from New York just before noon Wednesday as the swirling storm was set to engulf the island. The plane took off less than an hour later with a new group of passengers for the return trip to New York. Radar images showed it navigating a narrow path between Irma's outer bands to escape the storm.

Florida and other flights being canceled

Airlines have already canceled some 4,000 flights in and out of cities in Irma's path, according to the flight tracking site FlightAware, and more cancelations are in store for Florida travelers. But Delta says it has also added a number of flights and brought in larger planes to help people get out of cities in the storm's path.

American Airlines says it will begin shutting down operations in Miami, Fort Lauderdale, Fort Myers, Sarasota and West Palm Beach by Friday afternoon and cancel flights through the weekend. JetBlue Airways said Wednesday afternoon that it had canceled about 130 flights.

Southwest Airlines is canceling all flights through Sunday to/from Fort Lauderdale , Fort Myers and West Palm Beach, and will suspend flights to/from Orlando starting Friday afternoon.

American, JetBlue, United and Delta offered waivers letting customers change travel plans to Florida and the Caribbean without the usual charges for changing a ticket.

Hurricane insurance impact

One of Florida's biggest home insurers could take a big hit if predictions about Hurricane Irma prove true.

The state-run Citizens Property Insurance Corp. is strong enough to absorb the blow from the monster storm, industry experts say, but all the new claims could punch a hole in its finances, possibly leading to higher premiums in future years.

Flood insurance has dropped

An Associated Press analysis shows a steep drop in flood insurance across Florida, including the areas most endangered by what could be a devastating storm surge as Hurricane Irma approaches.

In just five years, the state's total number of federal flood insurance policies has fallen by 15 percent, according to Federal Emergency Management Agency data. Florida's property owners still buy far more federal flood insurance than any other state, but most residents in hazard zones are badly exposed.