Yes, snow delays and cancels flights regularly during winter months

Snow and ice on runways, taxiways, and aircraft surfaces force airports to slow down operations or stop them entirely. A runway covered in snow or ice requires longer distances for planes to take off and land safely, and planes cannot accelerate or brake normally on slick surfaces. When snow falls faster than ground crews can clear it, or when temperatures drop below freezing, airports must reduce the number of flights they can handle per hour.

Heavy snow also affects visibility for pilots and air traffic controllers. Runways become harder to see from the air, and planes need more space between them for safety. Airports typically close runways one at a time for plowing and de-icing, which cuts capacity in half or more. A single winter storm can delay hundreds of flights across a region in a single day.

Key Takeaways

  • Snow on runways forces airports to reduce the number of flights per hour, because planes need longer distances to take off and land safely.
  • Ground crews must plow and de-ice runways and taxiways continuously during snow, which takes time and closes some runways temporarily.
  • Aircraft themselves need de-icing before takeoff if snow or ice has accumulated on wings and engines, adding 15 to 45 minutes per plane.
  • Freezing rain and wet snow cause more delays than dry snow, because they create slicker surfaces that are harder to treat.
  • Delays often cascade across the country because planes and crews get stuck in the wrong cities, affecting flights hours or days later.

How snow affects the runway and taxiway

When snow accumulates on a runway, the surface friction changes dramatically. Planes need much longer to accelerate to takeoff speed and much longer to stop after landing. An airport may reduce its runway capacity from 60 flights per hour to 30 or fewer, depending on snow depth and how fast crews can clear it.

Taxiways—the paths planes use to move between the runway and the gate—also need clearing. If taxiways are blocked or icy, planes cannot move into position for takeoff, and arriving planes cannot reach their gates. This creates a bottleneck that backs up the entire airport. Ground crews use plows, brooms, and de-icing chemicals, but heavy snow falls faster than they can clear it in some cases.

De-icing aircraft before departure

Before a plane can take off in snow or freezing conditions, ground crews must spray de-icing fluid on the wings, tail, and engine inlets. This fluid prevents ice from forming during flight and removes ice that has already accumulated on the ground. The process takes 15 to 45 minutes depending on the aircraft size and how much snow is present.

De-icing fluid is expensive and must be applied by specialized trucks, so airports have a limited number of them. When many planes need de-icing at the same time, a queue forms. A plane waiting for de-icing cannot push back from the gate, which delays its departure and every flight scheduled after it.

Visibility and air traffic control delays

Heavy snow reduces visibility for pilots trying to land and for air traffic controllers watching the airspace. Controllers must increase the spacing between planes for safety, which means fewer planes can land per hour. Runways that are normally 2 to 3 minutes apart may need to be 4 to 5 minutes apart in heavy snow.

Blowing snow can also obscure runway lights and markings, forcing controllers to close a runway temporarily until visibility improves. Some airports have equipment that measures visibility automatically and triggers runway closures when conditions drop below safe limits. These closures are brief but frequent during active snowfall, and they add up across a busy airport.

Freezing rain and wet snow cause worse delays than dry snow

Freezing rain and wet snow create slicker surfaces than dry snow because they bond to the pavement and aircraft surfaces. Dry snow can sometimes be blown or brushed away, but freezing rain requires chemical treatment and takes longer to clear. Wet snow is also heavier, so it accumulates faster and is harder for plows to move.

Ice on aircraft wings is particularly dangerous because it changes the shape of the wing and reduces lift. Pilots cannot take off with ice on the wings, so de-icing becomes mandatory rather than optional. This means every plane needs the de-icing process, which overwhelms the limited number of de-icing trucks available.

How delays spread to other cities

A major snowstorm at a busy airport like Chicago O'Hare or Denver International affects flights across the entire country. Planes that should have left Chicago at 2 p.m. are still there at 5 p.m. because of delays. Those planes are now scheduled to arrive in New York or Los Angeles late, which pushes back their next departure from those cities.

Crews also get stuck in the wrong places. A pilot and flight attendants scheduled to work a 6 p.m. flight out of Denver may still be in Chicago because their incoming flight was delayed. The airline must find a replacement crew or cancel the flight. A single snowstorm can create a chain of delays and cancellations that lasts 24 to 48 hours after the snow stops falling.

What airports do to keep flights moving in snow

Major airports in snowy regions have large fleets of plows, brooms, and de-icing trucks ready before winter arrives. They pre-treat runways with chemicals to prevent ice from bonding to the pavement. Some airports have heated pavement systems that melt snow as it falls, though these are expensive and not common.

Airports also coordinate with airlines to reduce the number of scheduled flights during heavy snow. An airline might cancel 10 percent of its flights proactively to give ground crews time to clear the airport and de-ice planes. This prevents the cascade of delays that happens when too many planes are on the ground at once.

Frequently Asked Questions

How much snow does it take to delay flights?

Even 2 to 3 inches of snow can cause delays if it falls quickly, because ground crews cannot clear it as fast as it accumulates. Airports begin reducing flight capacity as soon as snow starts falling. The amount that causes cancellations depends on the airport's equipment and how fast the snow falls, not just the total depth.

Do all airports handle snow the same way?

No. Airports in snowy regions like Minneapolis, Denver, and Buffalo have extensive snow removal equipment and experience, so they handle snow better than airports in warm climates. An airport in Atlanta or Phoenix may cancel flights for 2 inches of snow because they have few plows and crews are not trained for winter operations. Northern airports can often keep flights moving through 6 to 8 inches.

Can pilots land in heavy snow?

Pilots can land in snow if visibility is adequate and the runway is clear enough for safe braking. Modern aircraft have instruments that allow landing in low visibility, but the runway surface must still provide enough friction for the plane to stop. If snow is falling so heavily that visibility drops below minimums, the airport may close temporarily.

Why don't planes just wait out the snow?

Planes cannot stay on the tarmac indefinitely because of fuel limits, crew rest rules, and passenger comfort. Federal rules limit how long a plane can sit on the ground before it must return to the gate or take off. If a plane cannot take off safely, it must go back to the gate, which ties up that gate and prevents other planes from using it.

Does snow delay flights the day after it stops falling?

Yes, often for 12 to 24 hours after snow stops. Planes and crews are still in the wrong cities, and airports are still clearing taxiways and de-icing equipment. Airlines need time to get their schedule back to normal. A major snowstorm can affect flight operations for two days even if the snow only fell for a few hours.