The massive Winter Storm Boreas,already blamed for at least 14 deaths, trekked east on Tuesday, spreading its travel misery with a dangerous mix of snow, sleet, ice and heavy rain. Thanksgiving travelers scrambled to book earlier flights to get ahead of the nasty storm.

By Wednesday morning, Boreas will impact the entire East Coast, likely creating havoc on the roads and in the air on the busiest travel day of the year.

The wintry weather started Tuesday in the interior Northeast. Buffalo, Pittsburgh and the Ohio Great Lakes region were hammered by Winter Storm Boreas' snowy side.

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“That’s going to be ground zero for the heaviest snow," said TomNiziol, winter weather expert at The Weather Channel. "Buffalo to Cleveland to Pittsburgh, if you have anything to get done today, get it done early. Because once this starts today, it will be a long time before it finishes. This is going to be a large-scale snowstorm for the entire region."

"The timing of the storm couldn't be worse," said Chris Vaccaro, spokesman for the weather service headquarters in Silver Spring, Md. "We are seeing numerous threats as the storm is beginning to develop and intensify."

Vaccaro said heavy rain and high winds would impact travel by air and road in the northeast and mid-Atlantic, and that the weather in that part of the country could have a ripple effect on airports with departing and originating flights elsewhere.

The FedEx Express Memphis hub and flight operations center announced Tuesday night that they experienced substantial disruptions Monday night due to the winter storm moving across the U.S. Potential delays are possible for shipment deliveries across the U.S.

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"By the time this is over, Winter Storm Boreas (the rain and snowy side) will affect more than 32 states and will have impacted more than 200 million people," said Niziol.

Dangerous Driving

As of Tuesday, Boreas was blamed for at least 14 total deaths in five states. Most of the fatalities were tied to traffic accidents.

Five people were killed on Texas roads during the weekend. In Oklahoma, the Department of Public Safety says four people died as a result of weather-related accidents.

Before moving into the Plains, the system hurled high winds, snow and flooding rains into the West and Southwest.New Mexico State Police say a four-year-old girl was killed in Roosevelt County Friday when her family's car slid off the road and overturned.Friday, firefighters in Tucson recovered the body of a man who was thought to be swept away by high water in the Santa Cruz River.

The system was also blamed for three wind-related deaths in California late last week.

Holiday Travelers Concerned

As the storm continues east, forecasters say heavy rains and strong winds could impact airports up and down the coast.

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"Some of those amounts could be very substantial," said Jim Robinson, meteorologist with the National Weather Service in North Little Rock. "Closer to the coast, there will be a big rain spell, I'm afraid ... from central North Carolina up into Maine: 2 to 5 inches."

Crews spray deicing solution onto an American Airlines 737 before departure at Dallas-Fort Worth International airport, Monday, Nov. 25, 2013. (AP Photo/Brandon Wade)

Some of the country's busiest airports - New York, Washington, D.C., Philadelphia, Boston and Charlotte, N.C. - could see big delays.

Most airlines are hoping the storms won't be too severe, allowing them to continue operating a nearly full schedule with few cancellations, but likely a lot of delays, said Daniel Baker, CEO of FlightAware, a global flight tracking service.

"Cancellations are used as a good, preventative measure to avoid cascading delays that can negatively impact travelers thousands of miles away," Baker said.

This holiday will likely see the most air travelers since 2007, according to Airlines for America, the industry's trade and lobbying group, with the busiest day being Sunday, an estimated 2.56 million passengers. Wednesday is expected to be the second-busiest with 2.42 million passengers.

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Ninety percent of travelers this week will drive, according to AAA, and an estimated 38.9 million people - 1.6 percent fewer than last year - are expected to drive 50 miles or more from their home.

MORE ON WEATHER.COM: Winter Storm Boreas

Traffic on I-35 at the 33rd street bridge in Edmond Sunday, Nov. 24, 2013. (Doug Hoke/The Oklahoman)