Jacksonville Mayor Lenny Curry declared a state of emergency Wednesday starting at 3 p.m. as Hurricane Irma pounded the Caribbean and continued to move toward the United States.

He said the uncertain path of the hurricane made it hard to tell if mandatory evacuations would be necessary in Jacksonville, but he encouraged people living in certain pockets of the city to evacuate early to avoid traffic from South Florida.

“I would prepare and I would begin to leave,” Curry said.

During an afternoon briefing with the National Weather Service, Curry said he was told by advisers Jacksonville could experience a heavy traffic problem late in the week and into the weekend due to people traveling north through the area to avoid the storm.

Jacksonville Sheriff Mike Williams said the best option for drivers leaving the area is to head north on Interstate 95 because Interstate 75 is the only other main artery out of the state and both will be clogged with evacuees.

Curry said people need to know which evacuation zone they are in and can find that out by going to the website jaxready.com. People can also reach various city departments at (904) 630-2489.

The city will close offices for non-essential employees, Friday while the status of Monday operations will be determined depending on the path of the storm, Curry said. He confirmed trash pickup will continue Friday to alleviate the amount of debris on the roads.

Live blog: Tracking Hurricane Irma

Latest Hurricane Irma tracking map

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All public schools in the county will have early dismissals Thursday and will be closed Friday through Monday, according to Duval County Public Schools. St. Johns County is closing all public schools Friday and will determine when to open again depending on the storm. Clay County public schools will be closed Friday through Monday.

Schools in Nassau County are asking students to monitor social media for closures.

Curry said it’s still far too soon to determine how much of an impact Irma will have on Northeast Florida, but it’s time to start preparing just in case. Another storm, Hurricane Jose, is growing right behind Irma, according to the National Hurricane Center.

Irma, a Category 5 storm, was about 40 miles northwest of St. Thomas and 55 miles east-northeast of San Juan, Puerto Rico, as of 5 p.m. Wednesday, according to the Hurricane Center. It had maximum sustained winds of 185 mph and was moving west-northwest at 16 mph.

Jose is gaining momentum with maximum sustained winds of 75 mph and was last located about 1,040 miles east of the Lesser Antilles as of 5 p.m., according to the Hurricane Center. It also was moving west-northwest at 16 mph.

Slideshow: Jacksonville prepares for Irma

Curry led a tour of the city’s emergency supply warehouse Wednesday morning to show some of the items the city has ready in case of a disaster. He said he wanted to show residents the city is prepared for the storm as officials are asking them to do the same.

The warehouse contains 120,000 liters of bottled water and the supplies needed to open 12 emergency shelters Friday. There are portable generators, large fans, emergency vehicles and non-perishable meals as well as other items at the warehouse. The locations of the shelters will be announced once they are all confirmed.

Curry explained JEA customers can take advantage of their tap water by bottling it ahead of the storm. He said the water is still clean to drink and residents should fill any containers that can make it through the storm.

County commissioners declared a state of emergency in St. Johns County during their meeting Tuesday as well. The county administration and emergency staff are monitoring the storm and encourage residents to get information at sjcfl.us/hurricane or by calling (904) 824-5550.

St. Johns County is providing free sandbags, but residents must provide their own shovels and transportation. They need to fill the bags on their own, according to St. Johns County Emergency Management.

There is a limit of 20 bags per person at the following six locations: Windswept Acres Park, 5335 S. Florida A1A; Sims Pit, 536 S. Holmes Blvd.; Hastings Town Hall, 6195 S. Main St.; Mills Field, 1805 Racetrack Road; North Beach Park, 3721 Coastal Highway; and under the Palm Valley bridge east of the Intracoastal Waterway.

Clay County is also monitoring the storm closely and will start passing out sandbags Thursday at the following locations: Middleburg Fire Station, 4003 Everett Ave.; Fleming Island Fire Station, 5995 Pine Ave.; Orange Park Fire Station, 2025 Smith St.; Green Cove Springs Public Works Yard, 900 Gum St.; and Keystone Heights City Hall, 555 S. Lawrence Blvd.

Residents in Clay County are encouraged to be aware of their evacuation zones and can monitor the situation at alert.claycountygov.com. People who live in mobile homes are automatically classified as living in an evacuation zone.

Meanwhile, residents are filling up at gas stations, and grocery and home improvement stores throughout the area. There have been scattered reports of gas stations running out of everything but premium gas.

City Councilman Reggie Gaffney toured the city’s supply warehouse along with the mayor Wednesday morning and said he was encouraged by the amount of water the city has on hand. Gaffney said the people in his district on the Northside were scrambling to find water Tuesday and he hopes stores will begin restocking their shelves soon.

Joe Caldwell, manager of corporate communications at Southeastern Grocers, said bottled water has been the most in-demand item at Winn-Dixie and Harveys stores throughout the state.

“We have trucks out on the road, restocking the stores as fast as we can,” he said. “The emphasis had been on South and Central Florida, but now the focus is shifting to North Florida. We’re able to pull trucks from the Tampa area and other states.”

He said many stores aren’t even bothering to restock the shelves with new shipments. Instead, full pallets of bottled water are being placed at the front of stores.

The area military bases are waiting to see if the storm turns toward Jacksonville before sending aircraft elsewhere, but Mayport Naval Station isn’t wasting any time getting ships to safety.

Ships started departing for safe waters Tuesday and will continue through Thursday. The USS Shamal, USS The Sullivans and USCG Tahoma headed to sea Wednesday.

The USS Philippine Sea, USS Farragut, USS Milwaukee, USS Lassen and USS Tornado are scheduled to depart Thursday.

In case of evacuation, officials in Jacksonville Beach, Neptune Beach and Atlantic Beach said that re-entry passes are not necessary for Hurricane Irma. Residents will need to present a Florida driver’s license and a proof of residency (vehicle registration or utility bill, for example) to re-enter the Beaches after the storm passes.

Jacksonville Beach officials said sandbags can be found at local hardware stores. Neptune Beach will offer sandbags to residents Thursday at Jarboe Park, 1408 Fifth St. Residents will need to present a valid ID with their Neptune Beach address to fill sandbags, with a limit of 10 per person. Atlantic Beach will announce where residents can get sandbags by Thursday morning.

Organizers are postponing and canceling events around the area as the storm moves closer to Florida.

The 15th Annual Ponte Vedra Auto Show was supposed to take place Sunday at the Nocatee Town Center, but it has been rescheduled for Sept. 24 at the same location. The event will run from 9 a.m. to 3 p.m.

“It is the prudent thing to do,” said Isabelle Rodriguez, president and CEO of the St. Johns County Chamber of Commerce. “We are acutely aware of the effect a hurricane can have on a community and while we are hoping for the best, we take seriously the consequences this imposing storm may inflict and we are planning accordingly.”

Several events are being canceled or postponed in the area due to the storm.

Thursday night’s Modest Mouse concert at the St. Augustine Amphitheatre has been canceled, and the Blackberry Smoke and Chris Robinson Brotherhood concert set for Friday at the same venue has been postponed. The Bryan Adams concert scheduled for Saturday at Daily’s Place has been postponed.

The weekly Riverside Arts Market held under the Fuller Warren Bridge was also canceled this week.

Area school systems are monitoring the storm and are asking parents to check social media for updates on when schools will reopen again.

The University of North Florida, Jacksonville University and Florida State College at Jacksonville announced they will be closed Friday through Monday. St. Johns River State College will close Friday and will stay closed until further notice. Florida Coastal School of Law will be closed starting at 6 p.m. Thursday until Tuesday.

The Clay County School Board has officially canceled Thursday’s meeting. They plan to hold two meetings in September to make up for the canceled meeting.

All state courts will be closed Friday and the Florida Commission on Ethics canceled their Friday meeting, but will cover items on the agenda at their meeting Oct. 20.

The Cummer Museum of Art & Gardens will be closed Friday and remain closed until further notice.

People need to make plans for their pets as well.

“Many pets went missing during Hurricane Harvey last week in Texas,” said Christian Broadhurst, senior staff veterinarian at Clay Humane. “Taking precautions ahead of the storm will help keep your pets safe.”

She recommended pet owners make sure their pets have tags that are up to date, proper crates or carriers for transportation, a supply kit with basic essentials and a list of area emergency shelters open to animals. If they require medication, it is important to have enough for several days.

People with medication needs of their own should take precautions now as well. Florida Blue will temporarily allow members to get early refills until Sept. 19 due to the storm at in-network pharmacies.

Curry encouraged residents to pay close attention to area news outlets for updates on evacuation orders if they become necessary. The sheriff said police will never physically force residents from their homes during a mandatory evacuation, but he said there’s a good chance authorities won’t be there to help when they are needed.

“There will be a point in this storm where we may not be able to respond,” Williams said.

Curry pointed to last year’s Hurricane Matthew and the recent hurricane devastation in Texas as reasons to prepare as early as possible and to leave the area if that’s the best option.

“I know this storm is a monster,” Curry said.

But he insisted if residents remain calm and continue to prepare for the worst, the city will make it through the situation together.

Times-Union staff writers Tiffanie Reynolds and Roger Bull contributed to this report.

Joe Daraskevich: (904) 359-4308