Sept. 6 (UPI) -- Floridians on Wednesday prepared to evacuate or hunker down as a ferocious Hurricane Irma kept the state firmly in its projected path.
Local officials in the South Florida's largest population centers ordered mandatory evacuations and prepared to open storm shelters. The storm, a Category 5, could approach the region by Saturday, according to the National Weather Service.
"Be prepared. Take it seriously," he said, echoing warnings he'd repeatedly stated on his Twitter page.
Tourists in Monroe County's Florida Keys were ordered to start leaving by 7 a.m. Wednesday and all county residents were told to start at 7 p.m.
In Broward County, which includes Fort Lauderdale, mandatory evacuations were ordered for Thursday in coastal and low-lying neighborhoods as well as mobile homes.
Fourteen shelters will be opened at noon Thursday.
"We're not going to knock on doors," Broward Sheriff Scott Israel said at a news conference. "We're not arresting people and we're not pulling people out of their homes. We're asking you to leave so you don't become a victim."
South of Broward, Miami-Dade County was planning to order evacuations of Miami Beach and mainland coastal areas Wednesday or Thursday, potentially displacing 420,000 people who could be affected by flooding.
The county urges evacuation when at least 18 inches of sea water flooding is possible.
"I'm personally recommending to our residents that you consider leaving the city of Miami Beach in advance of the evacuation order that we anticipate will be coming from the county mayor," Miami Beach Mayor Phili Levine said at a news conference.
Four county shelters will open Wednesday after schools close.
Most shelters are in schools, which will be closed for students and teachers Thursday and Friday throughout South Florida.
Palm Beach County plans to open 15 shelters Friday morning but has not announced any evacuation orders.
"If people are looking to leave the state, then they need to leave in plenty of time so they don't get caught in the evacuation," Palm Beach County Administrator Verdenia Baker said at a news conference.
Scott, appearing in Marathon in the Florida Keys, called up called up 900 more National Guard members after activating 100 Tuesday. The state's remaining 6,000 guard members must report for duty by Friday. On Tuesday, he ordered all state offices closed Friday and the suspension of tollway tolls.
The National Hurricane Center had issued no storm surge forecast yet for South Florida, but evacuation plans are being made in Miami Beach and other coastal areas.
"Storm surge and extreme winds are the biggest concern right now," he said. "The storm is biggest, faster and stronger than Hurricane Andrew."
Andrew, a Category 5 storm, hit South Florida in 1992, the most destructive hurricane to ever hit the state.
The South Florida Water Management District, which handles flood control from Orlando to the Keys, is lowering the water levels in drainage canals to accommodate the rain, said John Mitnik, chief engineer for the district.
The Army Corps of Engineers is planning to release water from Lake Okeechobee into the Gulf and the Atlantic. Herbert Hoover Dike, which holds back the waters of the lake, could be vulnerable to a breach if a strong hurricane hits.
Residents were preparing for the storm by purchasing food, water, gasoline, generators, flashlights, batteries and plywood to board up windows.
Many South Florida gas stations were out of fuel -- and the ones who weren't had long lines. All over the state, store shelves have been cleared of bottled water and batteries since Tuesday, when Irma strengthened into a Category 5 storm. Large retailers like Walmart and Home Depot were sending more supplies.
In Florida, it is unlawful to sell commodities, including gasoline, that "grossly exceeds the average price for that commodity during the 30 days before the declaration of the state of emergency" unless it can justify market trends.
But the price of gas has increased because of reduced supply from the Houston area because of Hurricane Harvey.
In Miami, the average price of a gallon of unleaded gas Wednesday was 2.75, which is 23 cents more than a week ago, according to Gas Buddy.
Another worry for residents is losing power.
Florida Power & Light, which serves 5 million customers, urged its customers to prepare for potentially prolonged power outages. Additionally, given the nature of the approaching storm and expected vegetation-related impacts on
FPL has invested nearly $3 billion to upgrade its equipment since Hurricane Wilma left most residents without power for days in October 2005.
Lack of cellphone service also was a problem. AT&T said in a news release it is "topping off fuel generators, testing high-capacity backup batteries at cell sites and protecting physical facilities against flooding."
With residents attempting to flee the area in planes, airlines are adding flights or using larger planes. Carriers are also offering fee waivers for those who want to cancel or reschedule their flights.
Key West International Airport announced it would close after the last commercial flight Thursday night, the first Florida airport to announce a shutdown.
Many residents said they learned from the mistakes they made when Hurricane Hermine hit last year. Others are motivated by the scenes of devastation in Houston, where Hurricane Harvey hit as a Category 4 on Aug. 25.
"We weren't really prepared for the last one. We were all like, 'yeah, whatever'. And this one is much bigger and much scarier so I think it's just throwing people off," Brittany Peters said in Tallahassee as she shopped for supplies.
Carnival Cruise Line reported that it has canceled two cruises -- Thursday's sailing of the Carnival Liberty from Port Canaveral and Friday's Carnival Victory cruise from Miami.
Norwegian Cruise Line canceled two cruises from Miami -- Friday's Norwegian Sky and Saturday's Norwegian Escape from Miami.
President Donald Trump, who declared a state of emergency in Florida on Tuesday, said he is closely monitoring the storm, which is the largest ever recorded in the Atlantic basin outside the Gulf of Mexico and Caribbean Sea.
"Watching Hurricane closely. My team, which has done, and is doing, such a good job in Texas, is already in Florida. No rest for the weary!" the president wrote Wednesday on Twitter.