NASHVILLE, Tenn. - A rare white Christmas in parts of the South was complicating life for some travelers as airlines canceled hundreds of flights, while snow was predicted for the nation's Capital and travel authorities warned of potentially dangerous roads.

The National Weather Service said the storm could bring 6 to 10 inches of snow to the Washington region, beginning today. The Weather Service was also forecasting significant snow for Philadelphia, New York and Boston, with as much as 18 inches falling on the New Jersey shore starting this morning and wind gusts up to 40 mph.

Virginia and North Carolina declared states of emergency on Saturday as airlines assessed whether to cancel flights for post-Christmas travelers.

Continental Airlines announced Saturday evening that it was canceling 250 flights departing from Newark Liberty International Airport outside New York City.

United Airlines said weather conditions would likely force delays and cancellations at United's hub at Washington Dulles International Airport and at other northeastern airports between Saturday and Monday.

"At this point, the forecast calls for less snow at Dulles" than in the New York area, United spokesman Michael Trevino said in an e-mail. "As a result, the team is still working through the plan for that station and whether any pro-active cancellations will be necessary."

Both carriers are waiving fees for one-time changes in affected areas and urged passengers to make changes through their web sites.

The Carolinas got their first white Christmas in decades as snow began falling Saturday morning in Asheville, N.C., spread to Raleigh by noon and was forecast to stretch to the coast later in the day.

The National Weather Service issued winter storm warnings with forecasts calling for up to six inches of snow in central North Carolina with more in the mountains and less on the coast. In South Carolina, forecasts called for rain turning to snow after dark.

It's the first Christmas snow for the Carolinas since 1989, when a foot fell along the coast. For Columbia, it's the first significant Christmas snow since weather records were first kept in 1887.

In Asheville, the Weather Service said snow fell at the rate of about an inch an hour earlier in the day and mountain roads would be impassable for all but four-wheel drive vehicles. As much as 10 inches could fall by this morning, which would break the previous Christmas Day record of 5.4 inches set in 1969.

North Carolina Lt. Gov. Walter Dalton declared a state of emergency Saturday.

The North Carolina Highway Patrol said most of the roads in and around Asheville were either covered or partially covered with snow and ice as of 6 p.m. Jarema said troopers in the two dozen westernmost counties answered 350 calls between 12:01 a.m. and 6 p.m. Saturday. Most of them were wrecks.

In the South Carolina Upstate, rain mixed with a light snow in the late afternoon, but it wasn't causing immediate road problems, said Highway Patrol Lance Cpl. Bill Rhyne.

In Nashville, some travelers who expected a smooth trip on Christmas got a rude surprise.

"We were hoping this was going to be a good day to travel," said Heather Bansmer, 36, of Bellingham, Wash.

She and her husband, Shawn Breeding, 40, had planned to return home on separate flights after a visit to Breeding's family in Bowling Green, Ky. However, Breeding's flight through Atlanta got canceled.

The couple was planning to spend much of Christmas Day in separate airports.

Brian Korty at the Weather Service in Camp Springs, Md., said travelers in the northern Mid-Atlantic region and New England may want to rethink travel plans for today.

"They may see nearly impossible conditions to travel in," he said. "It would be a lot better for them to travel today than it would be tomorrow."

In Pensacola, Fla., Jena Passut faced a quandary. The 36-year-old magazine writer drove with her husband and two kids from Fairfax, Va., to visit relatives. Now she worried about how to get back home amid the snow.

"Should we leave on Christmas night? My kids are normally good travelers, but if it's going to take us twice as long, it's going to be hell," she said. "I like a white Christmas as much as anyone, but I don't want to drive in it."

Authorities in the Mid-Atlantic states were preparing for the storm on Christmas Day.