ATLANTA – The lights were back on, but it was not business as usual at Hartsfield-Jackson International Airport in Atlanta after Sunday’s nearly 11-hour power loss caused more than a thousand flight cancellations.
And a thick layer of fog rolling into Atlanta on Monday morning threatened to make the holiday travel nightmare worse.
More than 400 flights had been canceled Monday at the world’s busiest airport and 42 flights had been delayed, according to FlightAware.com, following the massive outage that left travelers stuck inside airport terminals and in some cases aboard planes for hours.
That number was an improvement from the 1,173 flights and 207 delays on Sunday.
Approximately 30,000 people were affected by the outage, according to NBC News affiliate 11 Alive.
Delta, which is headquartered in Atlanta and had canceled approximately 900 mainline and Delta Connection flights on Sunday, accounted for nearly 300 of the flights canceled on Monday. The airline’s Twitter account said most of the cancellations on Monday were early morning, inbound flights.
Stranded Delta passengers at Hartsfield-Jackson hoping to get on a new flight were forced to wait in snaking lines for a new boarding pass after Delta’s electronic system went offline.
After obtaining paper boarding passes, travelers would once again undergo TSA security screenings.
One passenger waiting in the frustratingly long lines was Kiki Melanophy, 22, of Danbury, Conn., who was trying to get home after her graduation from the University of Alabama. She said she flew into Atlanta about 10 minutes after the power went out and spent five hours waiting to deplane.
Making matters more complicated was Blue, Melanophy’s 7-month-old cocker spaniel puppy travelling with her.
“We got here four hours before the flight this morning. I’m sure we won’t make it because they won’t let me check in with the dog,” Melanophy told NBC News during a phone interview.
Melanophy said her anxiety was spiking while waiting in the painfully slow line at the special services counter as she feared she would end up footing the bill for a new ticket home.
Meanwhile, Melanophy’s family, who had flown down from Connecticut for her graduation, had made it through the security line.
“They actually had to go through security without me. They’re getting on my plane,” she said of her family, adding that she told them to go on without her. “I’m hoping they make the flight. We were all coming home from graduation, and I just sent them through because my parents and siblings have work to get to.”
Related: Atlanta airport loses power, trapping travelers in planes and terminals
Incoming passengers on Sunday who had checked luggage were urged not to attempt collecting their bags on Monday due to the extreme congestion, the airline warned on Twitter.
Atlanta Mayor Kasim Reed said the outage, which began around 1 p.m. ET on Sunday, had been caused by a fire at the main substation powering the airport.
Firefighters and electrical workers were unable to assess the damage for nearly two hours due to the extreme heat and dangerous fumes.
It was not immediately clear what caused the fire.
“I want to express my sincere apologies to the thousands of passengers whose day has been disrupted in this manner,” Reed said Sunday during a news conference. “We certainly understand that the outage has caused frustration and anger and we are doing everything that we can to get folks back home right away.”
By 10 p.m. ET, all passengers had been deplaned, Reed said.
As the airport attempted to return to normal operations on Monday, a dense fog advisory was issued for the area from 2:44 a.m. ET until 9 a.m. ET, according to Weather.com.
Visibility was forecast to be less than a quarter mile in some areas, but it was not immediately clear if the fog would cause further delays to the already backed-up airport.
Kerry Sanders reported from Atlanta, Kalhan Rosenblatt reported from New York.