Accuweather.com said the storm gave Little Rock, Ark., its snowiest Christmas in 86 years.
The weather disrupted air travel and forced the cancellation of Wednesday's scheduled basketball game between the Chicago Bulls and Indiana Pacers in Indianapolis, which had been blanketed by 7 inches of snow by midafternoon.
Severe winds blew the snow across Ohio and Indiana. Accuweather said the snow is expected to mount up to more than a foot across the interior of the Northeast. But rain and strong winds, and a sometimes icy mix, would hit the Northeast coast.
The report cited snow accumulations Wednesday morning of 14 1/2 inches four miles south of Marion near the southern tip of Illinois and 6 inches in Muncie, Ind., with more snow falling and winds gusting to 30 mph.
The National Weather Service said Christmas Day storms produced dangerous winds and tornadoes and left more than 190,000 customers without power.
Weather-related deaths killed at least six people in Louisiana, Oklahoma, Texas and Arkansas.
A man driving in Houston died when a tree fell on his pickup, Harris County Sheriff's Deputy Thomas Gilliland said. The Dallas Morning News reported a homeless man in his 60s was found "frozen behind a church" in Old East Dallas Wednesday morning, according to a police report. The report said the man has yet to be identified, and the medical examiner's office will have to officially determine a cause of death, but overnight temperatures were dropping into the 20s and wind chills in the single digits.
In Woodward, Okla., a woman died in an accident on a snow-covered, two-lane highway and a man died when a tree fell on his home in Louisiana.
The Arkansas State Police said two toddlers were killed in an accident on Highway 36 near Mount Vernon that left their father and a female companion in critical condition. KTHV, Little Rock, reported the accident occurred when the driver of one vehicle lost control and plowed into a second vehicle heading in the opposite direction. The occupants of the second car also were injured.
Blizzard and winter storm warnings were in effect from the Deep South to New England and as much as 15 inches of snow was predicted for parts of Ohio and Pennsylvania to northern Maine and Canada.
Accuweather.com said flash floods were possible as the storm moves northeast to the central and southern Appalachians before heading into the Carolinas and Maryland, then out to sea.
Strong winds, predicted to hit 60 mph, were expected to whip the East Coast from Long Island, N.Y., to Boston.
David Saraceno told CNN he was driving on Interstate 165 in Mobile County, Ala., when he spotted a tornado about 2 miles away.
"I put the pedal to the floor to try to get out of harm's way but it seemed to be getting closer and closer," said Saraceno, who left the highway near Chickasaw and reversed direction to get out of the way.
"It appeared that the tornado turned and came over the interstate about three minutes away from where we would have been if I did not get off the interstate. We saw a roof that must have blown off a house. Cars were pulled to the side of the road. There was a lady whose windows were shattered. It was too close for comfort."
The (New Orleans) Times-Picayune reported a possible tornado damaged 25-30 homes, resulting in numerous injuries, in Ball, La. Police said another twister touched down in Zachary, La., but didn't cause extensive damage, the newspaper said.
The Times-Picayune said the Lake Pontchartrain Causeway was closed for a time because of hail and low visibility.
Police said a tornado apparently touched down near downtown Alexandria, La., injuring one person and damaging more than a dozen buildings, CNN said.
The National Weather Service said a tornado struck Mobile, Ala. Murphy High School history teacher Rick Cauley said he and his family rode out the storm in the school's field house. The twister destroyed an equipment barn and six mobile classrooms and damaged the roof of the school auditorium and band room.
"It was pretty horrific," Cauley said.
A spokesman for Mobile Fire-Rescue, Steve Hicks, said several other buildings, including a church, and the storm caused several traffic accidents.
Alabama's Choctaw and Clarke counties also reported damage and one person in Prichard was injured, CNN said.