Pinellas County ordered its first evacuations on Thursday as Hurricane Irma continued its march to Florida.

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Officials officials ordered everyone who lives in low-lying areas or mobile homes to evacuate. Access to beach communities will be restricted starting at 10 a.m. Friday. At 8 a.m. Sunday, that access will be cut off. Deputies will not allow anyone to re-enter those areas.

EVACUATION MAPS: Find evacuation maps for Hillsborough, Hernando, Pasco and Pinellas.

Those measures were all a part of the Pinellas County Commission's unanimous decision Thursday to issue an evacuation order for Level A residents — which includes mobile homes and low-lying areas — starting at 6 a.m. Friday. That order affects about 160,000 residents.

A decision on Levels B and C residents will be made Friday night, which could affect another 340,000 residents.

All told, that would mean 500,000 residents could be ordered to evacuate Pinellas County in the next 48 hours or so as the Category 5 storm draws ever closer to South Florida.

"This is a very serious moment," commission chair Janet Long said at the start of the emergency meeting.

Assistant County Administrator John Bennett told commissioners Pinellas could experience "tropical force winds" based on the current forecast, but the rainfall "does not look very high."

Bennett and Pinellas Sheriff Bob Gualtieri asked commissioners to issue the order early Friday so thousands of residents could leave before other zones could be told to leave early Saturday.

Both men cautioned that the storm could still shift west and force thousands more to evacuate Pinellas County.

Mobile home residents weren't shocked by the order. Still, several were uncertain about where they would go, and how they would get there.

"Where do we go? Is there some place to go?," asked Liz Meeks, 47, a two-year resident of Treasure Village off 52nd Avenue N and First Street in St. Petersburg. "I'm not sure what will happen to the woman next door who just moved in. She's in a wheelchair."

"No sir, we won't be prepared to evacuate," 67-year-old Martin Toney said after learning of the evacuation order. "I only have a bicycle to go ... This whole area could be wiped out."

Another neighbor asked a Tampa Bay Times reporter to explain the situation to his wife, who relies on a stomach pump and oxygen tank and is not easily moved.

If Irma continues on its current course, it could generate tropical-force winds and even tornadoes that could threaten mobile homes in the Tampa Bay region. Low-lying areas could also be threatened by flooding. Bennett, a former assistant Tampa police chief, said that's why it's essential to get residents out of low-lying areas before conditions worsen.

Starting at 10 a.m. Friday, the Pinellas County Sheriff's Office will restrict access to beach communities from the Dunedin Causeway to Tierra Verde. Only residents, business owners and their employees will be allowed in with identification.

Gualtieri said that way deputies can prevent local homes and businesses from being targeted by looters. An extra 30 deputies will be sent out to patrol beach communities.

"We will secure those areas safely and securely as we can," he said.

The restrictions won't be lifted, the sheriff said, until the storm has passed and the danger is over.

The county plans to release a list of seven shelters once the evacuation order takes place. Details are still being finalized.

Once the mandatory evacuation starts, residents can expect even heavier traffic because residents from South Florida are already traveling through the area to head north, Gualtieri said. To keep traffic flowing, 150 law enforcement officers will be posted on roadways throughout the county.

Gualtieri said residents should leave to avoid the crush of traffic on Friday. He stressed that Thursday's order is mandatory, but law enforcement will not be "going door-to-door and arresting people."

The order, he said, is to protect lives and keep residents safe. At some point, first responders might not be able to help people who wouldn't leave, he said. Those who stay in the Level A evacuation zone are taking a risk. If they find themselves in trouble during the storm, there may not be a way for help to reach them.

"We want people just to listen what been said. Take it seriously," Gualtieri said after the meeting. "It's a mandatory ask. But you run the risk at your own peril of not heeding the directive. Its in the interest of their own safety."

Need help evacuating? Residents with special needs can call the Citizen Information Center at (727) 464-4333 to register for a ride to a shelter.

In the Venetian mobile home park a few blocks north of Treasure Village, Alex Houget said he had nowhere to go and joked about riding out Irma with a bottle of vodka and his motorcycle.

"I'm staying right here with my bike," said Houget, 68, who said he lost everything in 1992's Hurricane Andrew when he lived in Miami-Dade.

Houget said he doubts Irma will be so bad — although it's already bigger, stronger and faster than Andrew. Still, he's keep an eye on the storm.

"I'm watching it," he said. "If it doesn't make that turn, and it's more than 100 mph, I'll find that shelter as long as I can take my bike.

"I'm crazy, but I'm not stupid."

His neighbor Bill Thayer, 61, said he's not taking chances.

"I'm not staying, not with the numbers they're talking about, 185 mph," he said. "No way."

At the Gateway mobile home park off Gandy Boulevard in St. Petersburg 81-year-old Wallace McAninch said he had finally found motel rooms on nearby higher ground for Saturday and Sunday nights. But he had no plans to evacuate before then.

"They saying you have to evacuate right now doesn't necessarily mean it's possible," said McAninch, who also had to move his 88-year-old mother-in-law to another family member's home.

"There's no point in panicking," he said. "They taught me that in the military — don't panic."

RELATED: Find your evacuation zone and emergency shelters

This is a developing story. Stay with tampabay.com for updates.