ATLANTA — Snow and blustery winds blew into the already-frigid East today and drivers as far south as Georgia were urged to stay off icy roads.

Arctic air continued to blanket much of the nation a day after a tractor-trailer jackknifed on a snow-slick Ohio road and hit a van carrying disabled adults, killing four people.

In Atlanta, more accustomed to temperatures in the low 50s this time of year, a glaze of ice coated roads today after light snow overnight melted and froze. Nearly 30 cars piled up in a pre-dawn crash near Hartsfield-Jackson Atlanta International Airport.

“I wanted to stay home today, but my boss never called me back, so I thought I should try to get in,” said Beth Ament, 30, who was fueling her car so she could get to a nearby transit station to take the train to her job in downtown Atlanta.

Multiple deaths have been blamed on this week’s cold, including a 44-year-old man whose body was found face-down in the snow early today in Billings, Mont. Schools in at least 10 states were closed, as were many roads and government offices.

The edge of the storm reached the Philadelphia area overnight, and up to 2 inches of snow was likely there and in the New York City area, according to the National Weather Service, which warned commuters to be careful trekking to work.

“People ought to take it easy when they get out on the road this morning,” Weather Service meteorologist Bill Goodman said early today.

Amtrak announced that its train between Chicago and Denver wouldn’t operate today because of blowing and drifting snow in Nebraska.

In Ohio, the Weather Service warned of a possible lake effect: arctic air blowing over the Great Lakes, picking up moisture and carrying it inland, creating narrow bands of heavy snow. A winter storm warning was in effect until Saturday morning.

That’s on top of the snow that had already coated Interstate 70, where a tractor-trailer spun out of control Thursday, crossed the median and swerved into oncoming traffic, colliding with a small bus transporting adult disabled passengers, the Ohio Highway Patrol said.

Three passengers on the bus were killed, as was its driver. Six other passengers on the bus, which was carrying 11 people, were injured, as was the driver of the commercial truck.

Snowfall was heaviest in Minnesota and parts of South Dakota, where blowing winds piled up drifts too big for snowplow drivers to clear. In Illinois, six snowplows were involved in accidents.

Nowhere was it colder than in Bismarck, N.D., where wind chills hit 52 below zero Thursday and the high temperature reached only 14 below. Wind chills were still near 50 below in the Dakotas for a second day.

While North Dakotans get plenty of practice with bundling up, folks in other parts of the country were still learning the basics.

With temperatures Thursday night on the Texas-Mexico border descending near freezing, officials in Laredo issued an advisory telling residents to “dress warmly and stay dry.”

In Florida’s panhandle, vapor was rising off the Gulf as warm water met the frigid air.

“It’s so cold that sparrows that have crawled under the plastic on our heated deck don’t want to leave,” said Scooter Montgomery, manager of Peg Leg Pete’s Oyster Bar on Pensacola Beach.