ATLANTA (RNN) – Power has been fully restored to Atlanta Hartsfield-Jackson International Airport after nearly a day with no electricity, the Associated Press reports, but even with the power restored, the massive outage will continue to affect Monday flights.

Delta Air Lines, which has its largest hub at the Atlanta airport, canceled 300 flights scheduled for Monday, according to the Atlanta Journal-Constitution. The company says its flight schedule is “expected to return to normal by Monday afternoon.”

The city of Atlanta announced on Twitter it would provide shuttle services to the Georgia International Convention Center for passengers who need a place to stay for the night, and the airport says parking will be free until 8 a.m. Monday.

Chick-fil-A made the rare gesture of opening on a Sunday to deliver more than 5,000 meals to stranded passengers, according to the airport’s Twitter page.

The airport says TSA checkpoints will open at 3:30 a.m ET.

The Federal Aviation Administration stated it will retain normal staffing in the airport’s Air Traffic Control tower, where aviation and cargo operations are now open.

Atlanta Mayor Kasim Reed tweeted around 7:30 p.m. ET that power at Concourse F of Atlanta Hartsfield-Jackson International Airport had been restored. It was one glimmer of hope for thousands of stranded travelers at one of the busiest airports in the world after a major power outage that shut down the airport early Sunday afternoon

At a media briefing Sunday night, Reed confirmed the outage was a result of a rare electrical fire in an underground Georgia Power substation at 1:06 p.m. He said it’s unknown how the fire was started but there is no evidence to suggest it was caused deliberately.  

The Atlanta Fire and Rescue Department arrived in five minutes, Reed said, but because of noxious fumes in the tunnel, Georgia Power workers could not access it. They began work at around 3 p.m. to get the power up and running. 

He said the airport has a redundant system that should have restored power to the airport immediately, but that system was damaged by the fire.

“The advice we received was that rather than give wrong information, we needed to wait and provide the truth,” Reed said when asked about a lack of communication with the public during the outage. “It takes the fire department about two hours to assess the situation. As soon as the scene cooled, they (Georgia Power) got to working. We then got Concourse F up and running.”

Reed emphasized that officials’ focus is on safety and security, and reiterated Georgia Power’s earlier statement that all power should be restored by midnight Sunday.

Georgia Power had announced  at 6:30 p.m. that it expected to have power restored to the Atlanta Hartsfield-Jackson International Airport by midnight Sunday, according to a tweet from the City of Atlanta. The news release also said the outage may have been caused by a fire in at Georgia Power underground electrical facility.

Emergency lights flashed, ground traffic came to a halt and inbound passengers are stuck on their planes after power was lost at Hartsfield-Jackson International Airport in Atlanta on Sunday.

Police announced shortly after 6 p.m. ET that they planned to evacuate the airport – some five hours after the initial power outage, the Atlanta Journal-Constitution reported. The AJC reported that all flights had been canceled and baggage is being held in a secure area.

In addition to all air traffic coming to a halt in Atlanta, the Federal Aviation Administration enacted a ground stop for all flights headed to Atlanta, meaning that they will not be allowed to take off until the stop is lifted. International flights are being diverted to other airports.

Southwest Airlines announced cancellation of all Sunday flights in and out of the airport as the power outage continued into the night, the company said on Twitter Sunday evening.

CNN reported all flights out of Atlanta have been canceled for Sunday and all arrivals have been halted. CNN also reported one concourse was evacuated due to what was described as a bad smell. 

The  Atlanta Journal-Constitution reported a pilot relayed a message to passengers saying a construction crew severed a power line that serves the airport. That report was unconfirmed, and Georgia Power said it was working with airport authorities to determine the cause of the outage.

Power was lost in the entire airport, Delta Airlines confirmed on Twitter.

There are reports from people at the airport that flights are delayed and inbound flights cannot deplane due to lack of power in the jetways.

Some passengers were removed from planes on the tarmac via portable staircases. At one point, there were at least 40 planes stuck on the runway and tarmac.

The outage was first reported about 1 p.m. Eastern.

Dozens of passengers have tweeted reports of planes stuck at the gate, power lost throughout the airport, pilots announcing diverted flights and TSA not allowing people off of stalled escalators.

It is not known how many flights may be affected.

It is raining in the Atlanta area, but it is not known if the weather played a role in the outage.

Passengers stuck on the train that moves passengers between terminals were rescued by firefighters. Escalators and elevators were also affected, but no word if anyone was stuck in an elevator.

Cars are also not allowed to approach the terminal to pick up stranded loved ones.

Country music star Travis Tritt tweeted he was stuck in Fort Lauderdale, FL, because of the outage.

A man dressed as Santa Claus told WSB-TV that he was spreading Christmas cheer to the stranded passengers and that “all the elves” were working to get the power restored.

Hartsfield-Jackson is the busiest airport in the world, serving 150 domestic destinations and 75 international airports in 50 countries. On average, 275,000 passengers pass through the airport each day.

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