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 said it was a tough day.

• Thousands of flights were canceled and travelers were stranded.

• Busy holiday travel and a winter storm were blamed for the debacle.

Southwest Airlines CEO Bob Jordan said Monday was a tough day and warned that Tuesday could be even worse.

Travelers and crew were stranded across the US after Southwest canceled flights.

Jordan was interviewed by The Wall Street Journal late Monday. We'll have another difficult day tomorrow as we try to get out of this.

This is the largest scale event I have ever seen.

Southwest canceled a majority of its flights on Monday. 6:30 a.m. The airline had canceled 2,474 flights on Wednesday.

Southwest said it would operate a third of its schedule for safety reasons. Affected customers will be contacted to alert them to their options.

The company blamed the problem on busy holiday travel and a winter storm. The Dallas-based airline said it had been fully staffed and prepared for the holiday weekend before the storm.

We apologized and acknowledged that we fell short.

The Department of Transport said Monday it was concerned by Southwest's "unacceptably high rate of cancellation and delays and reports of lack of prompt customer service."

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 hotels without power or water, and many working long hours. The attendants were left on hold for hours while they tried to find a place to stay.

Customers who book on flights between December 25 and January 2 will be able to rebook the same route on new dates at no extra cost.

A passenger told The Journal that he and his family traveled 19 hours from Kansas City, Missouri to Phoenix, Arizona after their Southwest flights were both canceled.

Some flights were canceled because flight crews ran out of time, according to a Southwest spokesman.

Southwest didn't reply immediately to Insider's request for comment.

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

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