Monday was off to an especially rough start for fliers, with more than 2,000 flight cancellations across the nation as of 4 a.m. ET, according to flight-tracking service FlightAware. Most of those cancellations were preemptive, canceled on Sunday by airlines that were reluctant to fly their planes and crews into airports forecast to receive poor weather.
Monday's problems came on the heels of about 2,000 cancellations on Sunday and another 480 on Saturday. Combined, about 4,500 flights have been grounded across the nation during that time.
Unfortunately for fliers, the cancellation and delay count seemed likely to grow -- perhaps significantly -- during the day Monday.
Most big airlines eased rebooking rules for passengers scheduled to fly through airports in the storm's path. Airlines advised customers scheduled to fly Monday to check ahead on the status of their flights before heading to the airport.
Monday's most-severe flight disruptions were being reported at Washington's Reagan National Airport, though major problems had popped up across the region by early Monday morning.
More than 500 flights -- more than half of the airport's entire daily schedule -- had been grounded at National Airport as of 4 a.m. ET. Most of those cancellations were made Sunday, though the number could grow with ice and snow beginning to overtake the D.C. area.
The storm was forecast to dump up to a foot of snow around the nation's capital by late Monday.
The Monday cancellation percentages were lower but still significant at the region's other two big airports, Washington Dulles (more than 20% canceled) and Baltimore/Washington (more than 30%).
Poor weather also was forecast Monday for New York and Philadelphia, metro areas that are home to four of the nation's busiest – and most delay-prone – airports.
More than 200 of Monday's flights had been canceled at New York LaGuardia as of 4 a.m. ET, a figure that represented nearly 15% of the daily schedule there, according to FlightAware. More than 10% of Monday's flight schedule had been canceled at New York JFK and Newark Liberty airports.
In Philadelphia – a big hub for American merger partner US Airways – more than a third of Monday's flight schedule had been grounded as of 4 a.m. ET, according to FlightAware.
A number of other busy airports were being affected as well. Among those reporting significant cancellation numbers for Monday as of 4 a.m. ET: Boston; Buffalo; Nashville; Norfolk, Va.; Pittsburgh; Raleigh/Durham; Richmond, Va.; and Westchester County, N.Y.
Even in Florida, FlightAware counted 5% of the entire Monday flight schedule as canceled as of 4 a.m. ET at the Fort Lauderdale and Orlando airports. Those were likely preemptive cancellations on flights that had been scheduled to fly to Washington, Baltimore or other points in the Northeast.
The worst-hit airport on Sunday was Dallas/Fort Worth, the biggest hub for American Airlines. More than 580 combined arrivals and departures had been canceled at that airport.