Both of Houston’s major airports continued to be closed on Tuesday due to winter weather, resulting in numerous flight cancellations.

George Bush Intercontinental and William P. Hobby airports were shut down starting at midnight Tuesday.

United Airlines and Southwest Airlines, which have significant operations in Houston, were notably impacted by the storm affecting the Gulf Coast, along with United’s regional partners.

Passengers received some advance notice and were offered more flexibility to change their itineraries.

To ease recovery once the storm passes, both carriers preemptively canceled most of the affected flights.

Why do airlines cancel flights ahead of time?

Airlines frequently cancel flights in anticipation of severe weather.

Former airline executive Robert W. Mann, Jr. explains that airlines usually have a clear assessment of how a storm might disrupt their operations.

“Airlines foresee that the arrival and departure rates at the airport won’t support their complete schedule, so they adjust their timetables to match the pace the (Federal Aviation Administration) can accommodate based on the weather and wind conditions,” said Mann, who is the president of R. W. Mann and Company, an independent consultancy for the airline industry, in an interview with YSL News.

The airport authority in Houston indicated the closure was due to unsafe road conditions in the area. Mann noted these factors also influence airlines’ decisions to cancel flights.

“If the weather makes it so that customers or crew members cannot safely reach the airport, that’s another reason to reduce the number of flights,” he explained. “You simply can’t maintain a full schedule in those situations.”

Houston’s George Bush Intercontinental serves as a key hub for United Airlines, meaning cancellations at this airport could disrupt flights nationwide for the airline. Although not a technical hub, Southwest lets its operations occur primarily from William P. Hobby Airport in Houston, and its closure could similarly disrupt the airline’s overall schedule today.

What should passengers do now

It’s uncertain whether the preparations made by Southwest and United will be effective, or how quickly the airports can resume normal operations.

“It will really hinge on the conditions at the airport and the surrounding roads in Houston,” Mann mentioned. “These aren’t typically cities and airports designed to handle five or six inches of snow, potentially not even one or two inches.”

Nonetheless, if the preemptive measures by airlines and airports were effective, operations are likely to return to normal soon after the storm passes.

“It serves as a valuable test of planning and readiness, both in terms of clearing snow and de-icing procedures,” Mann added.

Zach Wichter is a travel reporter who authors the Cruising Altitude column. He is based in New York.