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Winter storms wreak havoc on flights. Here’s why.

De-icing, closed runways and crew schedules can lead to serious delays and cancellations

(iStock/Washington Post Illustration)
8 min

As if the holidays weren’t stressful enough, a monstrous winter storm is blanketing the country and upending travelers’ plans. For many airline passengers, this means significant delays or canceled flights, missed connections and cold Christmas ham.

Before the arrival of a “bomb cyclone” and blizzard conditions, major airlines were waiving change fees and fare differences for travelers scheduled to fly in the Midwest and Northeast in the days leading up to Christmas.

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Air travel “is like a fine-tuned Swiss watch, and you’re throwing sand into when you have winter weather,” said John Nance, a former military and commercial pilot and an aviation analyst with ABC News.

To better understand how winter storms affect flights, we spoke with aviation experts about some of the biggest mysteries surrounding icy and snowy weather and flying.

Planes and ice don’t mix

During winter storms, the biggest challenges are on the ground. Planes, like butterflies and cars, don’t like ice and snow on their wings or under their tires.

For planes to safely take off and land, they must be steady on their wheels.Pilots also need full braking capabilities, to slow and stop the plane after touching down. Without this ability, the plane can overrun or careen off the runway, as a Southwest Airlines tragically did in 2005. During an early December snowstorm, the plane landed at Chicago-Midway airport and skidded into a busy street, killing a young boy.

“Freezing rain terrifies us, and it should,” Nance said. “The principal concern is traction. If you have ice, you have nothing to grip.”

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The airport is in charge of clearing the runways, ramps, taxi ways and pedestrian walkways. The treatment depends on the type of precipitation: chemicals to thaw ice, for instance, and plows to remove snow.

“Powder snow, slush, ice — there are different removal systems,” said Hassan Shahidi, president and chief executive of the Flight Safety Foundation, a nonprofit advocate for air travel safety. “The airports test the condition of the runways with special equipment for traction.”

If the airport cannot keep up with snow or ice accumulations, the airport will have to close runways or the entire facility. In early February, for example, icy conditions forced Dallas-Fort Worth International Airport to shut down for several hours. The airport eventually reopened one of its seven runways, hampering flight schedules around the country.

“It ripples throughout the system,” Bill Feist, a commercial pilot with more than 30 years of experience, said of the long-tentacled effect of airport and runway closures.

A plane can’t take off if its wings are covered in even a light dusting of snow, ice or frost, which can interfere with the aerodynamics of the aircraft. “Ice and snow on the wings can disrupt the air flow,” Nance said. “It reforms the air flow over the wings.”

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To melt the precipitation, the plane must undergo de-icing, a process that involves spraying a heated chemical mixture on the wings, tail, fuselage and windshield. The treatment, which takes several minutes, plus any wait time for the de-icing machine, must occur immediately before departure. If the plane idles on the tarmac for too long, the precipitation can build up again.

“There is a 30-minute window after de-icing,” Shahidi said. “[A second round of de-icing] happens once in a while.”

To streamline the process and reduce potential delays, many airports have installed de-icing complexes. Last month, Memphis International Airport unveiled its Consolidated De-Icing Facility, which is considered one of the world’s largest, with 12 bays for commercial and cargo planes. “They pull up to the pad right before take off,” said Glen Thomas, a spokesperson for the Memphis International Airport.

Memphis is a FedEx hub, which works to passengers’ advantage: The airport has 44 pieces of winter weather equipment, such as plows, salt spreaders and snow grooming machines.

Why your flight may be delayed or canceled

When you see a “delay” notice on the airport’s electronic departures board or receive a message from your carrier that your flight has been canceled during bad weather, you can genuinely thank the airline. The airlines’ primary objective is to keep passengers safe.

“The airlines err on the side of safety and caution,” Nance said. “They do not like to take chances.”

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To that end, the airlines consult with two main entities: the Federal Aviation Administration and the airports. Like a professional counselor, the FAA doesn’t tell the airlines what to do; its role is to relay information and share communications. “The FAA does not encourage the airlines to delay or cancel flights,” said Greg Byus, the agency’s air traffic manager at the Air Traffic Control System Command Center in Warrenton, Va. “It is up to each individual airline.”

Your guide to surviving airport chaos

One of the FAA’s primary responsibilities is to “manage capacity and demand,” Byus said, by regulating how many planes can take off and land in an hour. If severe weather is obstructing the flow of air traffic, the FAA might issue a ground stop (no planes can land at the impacted airport) or a ground delay (a trickle of aircraft can touch down). The agency works closely with National Weather Service and the National Oceanic and Atmospheric Administration when making these decisions. The ground stop and delay directive only applies to departing planes, which might confound passengers who are sitting at the gate watching planes taxi down the runway while their plane is nowhere to be seen.

“Restrictions on arrivals are different than departing. The pilots need to see the runway,” Byus said.

Travelers departing from airports outside the weather system might also wonder why they aren’t boarding. The explanation: The airline will detain planes if there’s a chance that they can’t land at their connecting or final destination. This action will save the pilot from having to fly around the airspace until it is safe to descend or to divert to an alternate airport.

“A low ceiling, low visibility or heavy snow — airlines can’t dispatch to that airport,” Byus said. “The pilots can’t land.”

If the airline foresees runway or airport closures, it may preemptively cancel flights. This could be the situation that unfolds this week: According to AccuWeather, the impending storm could affect two-thirds of U.S. flights. “There are a lot of proactive, prophylactic cancellations,” Nance said.

To save yourself the stress of the unknown, take advantage of the waivers airlines are offering and depart before the storm arrives, if possible.

“I’ll get up at 4 a.m. if I have to, to get out before the storm hits at 9 a.m.,” said Jon M. Nese, a meteorologist and assistant professor at Pennsylvania State University. “I am a firm believer in getting out before the storm begins.”

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If you travel after the storm, factor in the cleanup time for both the roads and runways. According to Nese, winter storms in cities such as Boston, Philadelphia or St. Louis typically last from 12 to 24 hours. Storms linger longer — 24 to 36 hours — at destinations on lakes, such as Buffalo, which sits on Lake Erie.

How to avoid getting stuck this winter

It might be too late for this holiday, but winter has just begun. If you’re planning to travel between now and spring, you can take several steps to minimize disruptions.

Avoid connecting flights, so you don’t have to contend with multiple takes-offs and landings and accumulated delays. If possible, choose airports that are well-equipped for winter weather and large volumes of passengers, such as Boston Logan, Chicago-O’Hare and LaGuardia and JFK airports in New York. Conversely, small airports with limited resources and infrequent snowfalls are often less adept at handling the challenges of Arctic weather.

“Denver has a very good plan for removing snow,” said Byus, “and Buffalo prides itself on removing snow. Atlanta shuts down.”

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Consider booking a morning flight, when the flight crew has just punched the clock and the risk of their working hours expiring is low. Plus, bad weather can cause a cascade of delays throughout the day. To stay abreast of any changes in your flight, download your airline’s app. Nese also suggests tracking the weather using a radar app or following the National Weather Service. “It doesn’t take rocket science to understand the radar apps,” he said, with a caveat: “They don’t forecast. They are instantaneous.”

Winter storm clouds are not as tall as thunderstorm clouds, so pilots can easily soar above them, a respite from the drama on the ground.

“You can easily fly over a winter storm,” Nese said. “There could be a big blizzard below and you’d have no idea.”