Air travel is snarled at Midway and O’Hare as Chicago inches out of deep freeze. Feds call Southwest’s performance ‘unacceptable.’

Updated story: Southwest cancellations continue as airline says only one-third of flights across US will operate for ‘several days’

Although Chicago’s cold spell was showing signs of ending, the same couldn’t be said for the effect the weather still was having on holiday travelers using the city’s two major airports Monday.

Southwest Airlines was a target of much of the ire leveled toward airlines on Monday, with the majority of its flights canceled and would-be passengers taking to social media to unleash their anger. By the evening, the U.S. Department of Transportation announced it is looking into the “unacceptable” level of disruption for the airline’s customers.

“USDOT is concerned by Southwest’s unacceptable rate of cancellations and delays & reports of lack of prompt customer service,” the agency tweeted. “The Department will examine whether cancellations were controllable and if Southwest is complying with its customer service plan.”

As of 5:40 p.m. Monday there were 130 canceled flights out of O’Hare International Airport and 304 out of Midway Airport, according to the Chicago Department of Aviation. Average delays were roughly 30 minutes at both airports.

That was after below-zero temperatures and dangerously cold wind chills hit Chicago before Christmas, paralyzing travel throughout the U.S. Sunday brought a reprieve with the number of cancellations falling into the dozens, but the airports were once again crowded with grumbling travelers Monday.

Southwest Airlines accounted for 69% of canceled flights at Midway Monday, according to FlightAware. In a statement the airline attributed its disruptions to “continuing challenges” from the previous storm.

“With consecutive days of extreme winter weather across our network behind us, continuing challenges are impacting our Customers and Employees in a significant way that is unacceptable,” the statement read, adding that “we’ll work to make things right for those we’ve let down, including our Employees.”

A statement from Delta Air Lines also cited the recent weather for cancellations: “While the bulk of the severe weather has passed, some cancellations subsisted through Monday due to damage to airport infrastructure, frozen equipment, and continued restrictions on some otherwise routine ground operations.”

American Airlines saw minimal cancellations as of early Monday afternoon at O’Hare, but the three that occurred Monday were due to the airport closure in Buffalo, New York, over extreme snow, a spokesperson said.

Nonetheless, the city could see highs going up to the 50s later this week, spelling a potential 60-degree upswing in temperatures since the worst of a massive winter storm that swept through much of the U.S. right before Christmas, National Weather Service meteorologist Casey Sullivan said.

“We had a storm system move through; it brought down a big surge of cold air,” Sullivan said. “And now we have another storm system that’s going to be off to our west that’s going to allow the warm air to surge back up into our area.”

For now, however, temperatures were to dip to 8 degrees Monday night, then on Tuesday, Chicago is expected to hold steady with a high of 27 degrees and a low of 24. Temperatures will then rise to a high of 40 degrees Wednesday, with a slight decrease to 36 degrees at night.

On Thursday, the city could see highs up to 53 degrees and a low of 43, in conditions that will be about 60 degrees warmer than the coldest morning of the winter storm — minus 8 last Friday.

“Thursday looks like the warm day,” Sullivan said.

Friday is expected to see that balminess hold with a high of 48 degrees and a low of 35, and Saturday will have a high of 42 degrees and a low of 36 degrees heading into New Year’s.

The weather patterns might seem erratic, but it’s a typical shift during a La Nina winter, Sullivan said. During those months, cooler air from the Pacific Ocean drifts through the U.S. and sparks more “active” weather changes.

“Is it normal of any winter? Not necessarily,” Sullivan said. “It does happen but it is sort of normal for a La Nina winter because La Nina winters are just very active. And that’s what this winter is shaping up to be.”

At the Southwest check-in section inside Midway Monday afternoon, passengers sat slumped on the waiting area seats underneath glittering Christmas decorations, discussing backup plans — and backup plans to those backup plans — with family and with strangers.

Both Stacey Pastor, of Ohio, and Patti Snyder, of Lake Jackson, Texas, said they had their flights canceled Monday and had scoured the Southwest website for other options for hours, with little success. Their search for a rental car to drive to their destinations was just as fruitless given the rush for vehicles. Finally, Snyder said she and her husband booked a return flight — but it was scheduled after New Year’s Day.

“I’m hungry. I haven’t had anything since breakfast. It’s just a cacophony of screw-ups,” Snyder said. “We’ll eventually find our way home. It may be next week sometime, but we’ll get there. … Such is life.”

Pastor, meanwhile, also was missing her luggage after traveling for the last two days. But with or without it, she hoped to drive all the way to Denver on the longest road trip she’d be on yet.

“It’s gonna be tiring,” Pastor said. “The kids aren’t too happy about it.”

But despite the logistical nightmares placing a damper on the holidays, some travelers found unexpected help on Monday after all.

Portland resident Mark Belton, who landed for a layover in Chicago only to find his Southwest flight to Baltimore canceled, said his friends from the eastern city offered to drive to Chicago and drive him back to Baltimore should he not succeed at finding a new flight or a rental car soon.

“They’re really good friends,” Belton said with an exhausted smile.

David Zacharias, meanwhile, was in a good mood Monday as he and his wife, Sandy, drove to Midway in their rental car after spending a “wonderful” Christmas with their children, he said. They expected to fly home to Phoenix on Southwest, only to find their flight canceled and their returned rental vehicle long gone. And the options for flights from other airlines were running upward of $12,000.

Sandy Zacharias noted that they were far from alone, having waded through swarms of other travelers at the terminal before turning back.

Southwest spokesperson Chris Perry said, “Our rebooking system is receiving historic levels of traffic right now. Our team is aware and we are working on the issue. We hope traffic levels will subside and we apologize for the long delays.”