A massive storm system was marching toward the Northeast on Wednesday, upending post-Christmas travel plans after dumping snow and sleet on the middle of the country on Christmas Day and producing tornadoes through the South.
The storm, which stretches from Michigan to Florida, has been blamed for six deaths so far.
As the storm moves from the Tennessee Valley to the Mid-Atlantic, heavy snowfall, tornadoes and significant icing are possible, the National Weather Service said.
PHOTOS: Northeast braces for winter storm
The storm could dump as much as 18 inches of snow from western New York to central Maine. In a region stretching from the upper Ohio Valley to the interior Northeast, residents and travelers may see 6 inches of snowfall.
Travelers had to find ways to cope after more than 850 flights across the United States were canceled Wednesday as of 1 p.m. ET, according to FlightAware.com. The airports hardest hit are in the path of the storm.
Blizzard warnings were in effect for portions of Ohio and Indiana late Wednesday morning. A tornado watch is in effect until 5 p.m. ET for eastern North Carolina and northeastern South Carolina.
There is also a “moderate risk of severe weather along the coastal Carolinas," the National Weather Service said.
“It is a significant storm in terms of its size and its range of impacts from severe weather to winter weather,” said Chris Vaccaro, spokesman for the National Weather Service.
On Christmas Day alone, the National Weather Service received 34 reports of tornadoes in eastern Texas, Alabama, Louisiana and Mississippi, Vaccaro said.
Major cities along the I-95 corridor, which runs from Maine to Florida, could at first see a mix of snow or sleet, but the precipitation is expected to be primarily rainfall, he said.
As several states in the South began cleaning up Wednesday from as many as 19 tornadoes, the death toll rose when a car on a sleet-covered highway in Arkansas crossed the center line and struck an SUV head-on, killing two passengers in the car, the Associated Press reported.
In Oklahoma, two people were killed in separate crashes Tuesday. Earlier Christmas Day, the storm's winds were blamed for toppling a tree onto a pickup truck in Texas, killing the driver, and knocking another tree onto a house in Louisiana, killing a man there, the AP said.
Vaccaro said that by Friday, the storm should have largely moved on to Canada. “Come Friday morning, it will largely be a sunny day across the eastern third of the country,” he said.
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