Southwest Airlines' CEO described Monday's operational meltdown, which left thousands of travelers stranded across the US, as 'a tough day'

• Southwest Airlines CEO Bob Jordan described Monday's operational meltdown as "a tough day."
• The debacle saw thousands of flights canceled and left travelers and crew stranded across the US.

Southwest Airlines CEO Bob Jordan described Monday's operational meltdown as "a tough day" as he warned that Tuesday could be equally painful.

Southwest continued canceling flights Tuesday after Monday's debacle left travelers and crew stranded across the US.

"We had a tough day today," Jordan said in an interview with The Wall Street Journal late Monday. "In all likelihood we'll have another tough day tomorrow as we work our way out of this."

He added: "This is the largest scale event that I've ever seen."

Southwest canceled 71% of its schedule, or 2,909 flights, on Monday, according to data from flight-tracking service FlightAware. By 6 a.m. ET Tuesday, the airline had canceled 2,503 flights for the day and 2,474 for Wednesday.

Southwest said Monday it would operate about one-third of its schedule "for the next several days" for safety reasons. It said it's contacting affected customers to alert them to their options.

The company attributed the meltdown to a combination of busy holiday travel and the bitter winter storm that's battered the US. The Dallas-based airline said it had been "fully staffed and prepared" for the holiday weekend before the storm "forced daily changes to our flight schedule."

It added: "We recognize falling short and sincerely apologize."

The Department of Transport said Monday it was "concerned by Southwest's unacceptable rate of cancellations and delays & reports of lack of prompt customer service," adding: "The department will examine whether cancellations were controllable and if Southwest is complying with its customer service plan."

TWU Local 556, which represents Southwest flight attendants, said the disruptions had left "thousands" of crew members stranded, with some having to sleep on cots in airports or in hotels without power or water, and many working long hours "well past acceptable duty days." Attendants calling the airline were left on hold for hours while they attempted to find accommodation and their next routes, the union said.

Southwest said it's offering a system-wide waiver, allowing customers booked on flights between December 25 and January 2 to rebook the same route on new dates within two weeks of their original departure time at no extra charge.

One passenger told The Journal that he and his family drove around 19 hours from Kansas City, Missouri to Phoenix, Arizona after their Southwest flights from two different airports were both canceled, including one after passengers had already boarded.

A Southwest spokesperson told The Journal that some flights were canceled after boarding because flight crews ran out of allowable work time.

Southwest didn't immediately respond to Insider's request for comment, made outside of regular working hours.

Southwest said it was experiencing "extremely high call volumes" because of customers calling about the disruptions, with hold times averaging more than two hours and as high as four hours.