Philadelphia International Airport had about 593 canceled arriving and departing flights as of Tuesday afternoon.

Airport spokeswoman Victoria Lupica said at 3:30 p.m. there were "very few people" in the terminals. She said one runway was open, and the airport was operational.

"Crews are working tirelessly to keep all paved surfaces clear," Lupica said.

Airport officials had a conference call with airlines, the Transportation Security Administration (TSA) and Federal Aviation Administration (FAA).

"For the most part, airlines are winding down the operations and preparing for the evening and getting back to normal tomorrow," Lupica said. "We are planning for another 40 departures, including US Airways international arrivals and departures" which land and take-off in late afternoon and evening.

US Airways spokesman Todd Lehmacher said Philadelphia's dominant airline, which transports 70 percent of passengers here, "is still operating. Flights are taking about 90 to 100 minutes to get airborne with deicing, slow taxis, and snow removal."

Lehmacher said in an e-mail at 4:10 p.m. Tuesday: "We've thinned out our morning departures with select cancelations" for Wednesday "since we are reducing the number of aircraft coming in this evening (aircraft scheduled to remain overnight)."

"Both Pittsburgh and Charlotte will be receiving additional aircraft [Tuesday night] usually destined for Philadelphia and other impacted cities," Lehmacher said. US Airways expected all trans-Atlantic departures to operate Tuesday evening.

"Travelers we spoke to are in communication with their airlines to reschedule affected flights," Lupica said.

The airport was fully staffed and prepared to clear snow on all paved surfaces and the deicing facility "is open and ready to manage," Lupica said. "We are also fully prepared to manage customer needs in the terminal building."

Passengers were urged to check with their airline on flight status, call 1-800-PHL-GATE, or visit the airport website,