Airlines already canceling Wednesday flights for new winter storm

WEDNESDAY UPDATE: Wednesday was shaping up to be a rough day for air travel as a sprawling winter storm brought ice and snow to airports from the Great Plains into the Northeast. Cancellations were at 1,200 and counting ... . Full story: Snow! Flight cancellations at 1,200 (and counting) from new storm

PREVIOUS UPDATE: Airlines are canceling flights and expanding their rebooking waivers ahead of a new winter storm that looks increasingly likely to disrupt flights at airports from the Great Plains into the Northeast.

More than 470 flights had already been canceled for Wednesday, flight-tracking service FlightAware counted as of 5:40 p.m. ET on Tuesday.  

More than half of those preemptive cancellations were made by Southwest, canceled about 256 flights. United also began preemptively cancelling flights, with spokeswoman Maddie King telling USA TODAY's Today in the Sky blog that the carrier was "significantly reducing" its United Express regional flights at Washington Dulles from Tuesday evening into Wednesday. Washington Dulles is a major hub for United. 

Many of Southwest's cancellations appeared to come at Baltimore/Washington and Chicago Midway. The airports are the busiest two in Southwest’s entire network based on the number of daily departures.

Though both airports were expected to see wintry weather, Southwest's cancellations for Wednesday came as it was already experiencing a relatively high rate of cancellations in the days before the storm’s approach. The airline last week declared an operations emergency after an unusually high number of aircraft were taken out of service for last-minute maintenance work.

On Tuesday, for example, Southwest had canceled more than 180 flights, or 4 percent of its schedule, more than any other carrier as of 5:40 p.m. ET, according to FlightAware.  

USA TODAY:Snow, ice, torrential rain bringing weather havoc to 39 states, 200 million people

That was on top of 84 Southwest cancellations on Monday and 112 on Sunday.

Still, the cancellations were being made amid a forecast of wintry weather across the upper Midwest, Great Lakes and parts of the Mid-Atlantic and Northeast on Wednesday. A mix of snow and ice was possible at many busy airports in the region. Up to a half foot of snow was possible around Washington and Baltimore, though the precipitation was expected to end as rain there amid rising temperatures.

Airlines were issuing flexible rebooking policies as the poor weather approached.

USA TODAY TRAVEL:Southwest declares operations 'emergency' amid labor dispute with mechanics

American, Delta, JetBlue and Frontier rolled out change-fee waivers on Wednesday while Southwest and United expanded ones already in place.

More airlines were likely to follow.

For now, Delta’s covered Wednesday travel to nine airports from the greater New York City area south through Philadelphia and into Baltimore and Washington.

United, which had been waiving change fees for Tuesday flights to Chicago O’Hare, expanded its policy to include nearly 50 airports. United’s policy covered Tuesday flights to 10 airports in the Great Plains and Wednesday flights to the others, which spanned from Minnesota and Wisconsin east to Pennsylvania, Maryland and Virginia.

Southwest had two policies, one covering the "Midwest" and the other the "Ohio Valley and Northeast." More than two dozen airports were included, with either Tuesday or Wednesday flights covered depending on the city.

American's waiver focused on the Northeast, covering 11 cities -- including its hubs at New York JFK and Washington Reagan National. 

JetBlue’s waiver, also issued on Wednesday, covered Wednesday flights at six airports (Baltimore/Washington; Minneapolis/St. Paul; Philadelphia; Pittsburgh; Richmond, Virginia; and Washington Reagan National).

At Frontier, Wednesday customers flying from 24 airports from New York state to North Dakota and Nebraska were covered. 

The policies varied by carrier, but -- generally -- they allowed customers to make one change to their itineraris without paying the standard change fee that can cost $200 or more. 

Contributing: Dawn Gilbertson

IN PICTURES: 32 cool aviation photos