Two people were killed and dozens were injured when a gasoline tanker skidded off an ice-covered Baltimore highway and exploded, sparking a 55-vehicle pileup as a winter storm brought snow and ice to the Mid-Atlantic and Northeast, authorities said.

"When I looked up I saw a lot of trailers slamming on each other going 50 miles per hour. Basically they were piling up at 50 miles per hour,” eyewitness Marvellous Amasiatu said of the 4:45 a.m. pileup on the elevated portion of I-95 in downtown Baltimore near the Washington Boulevard exit.

"Oh my God," he said. "I could see those trailers coming. They had no idea how bad that bridge froze."

The driver of the tanker truck was killed and one other person died in the pileup, which was sparked by debris from the tanker crash and explosion, Maryland Transportation Authority Police Lt. Kevin Ayd said. The cause of the crash is under investigation.

Winter storms and frigid temperatures that have affected large parts of the country have been blamed in 13 deaths since Tuesday and hundreds of car crashes. At least seven people were killed in crashes since Friday night.

A third person in Maryland was killed Saturday morning after he stepped out of his car on I-95 to inspect damage from a fender-bender and was struck by a vehicle, Ayd said. More than two dozen people were injured in the pileup, four of whom were in critical condition, NBC affiliate WBAL-TV reported.

Two people were killed in crashes in the Charlotte, North Carolina area Saturday morning, accidents police said were due to icy conditions, NBC affiliate WCNC reported.

Two separate crashes in Indiana between Friday night and Saturday night left two people dead, and more freezing conditions were expected Saturday night, state police said. Overall state police responded to more than 400 crashes and 200 slide offs between 10 p.m. Friday to 10 p.m. Saturday — and seven state police vehicles got stuck, police said.

In Maryland, Gov. Larry Hogan said “road conditions in many areas of the state are still extremely dangerous, and all those who can avoid travel should stay off the roads until conditions have improved.”

Parts of Baltimore County and the city one-fifth of an inch of ice was recorded, the National Weather Service said, and near-freezing temperatures were expected in Maryland, extreme northern Virginia and eastern West Virginia Saturday night.

Trucks and vehicles are shown in a pile-up involving a fuel tanker which skidded off the an icey 1-95 highway in Baltimore on Dec. 17. Sage Hiller / via Reuters

In New Mexico, state police also reported a pileup that included "approximately 40 vehicles" on Interstate 40 Saturday morning. According to law enforcement, the roadway is covered in snow and ice, but they have not confirmed that the accident was caused by the inclement conditions and have not reported any deaths or injuries.

In St. Louis, the fire department reported more than 50 vehicle accidents and 40 falls. A firefighter was also struck by a vehicle and remains in serious but stable conditions.

Two to five inches of snow were reported to have accumulated across the Northeast and a second bout of cold was expected to create icy conditions. The wintry precipitation is expected to taper off, ending by late Sunday after leaving treacherous conditions in the Mid-Atlantic region, forecasters said.

“It’s pretty much winding down especially in the Northeast,” said Senior Weather Channel Meteorologist Dave Houtz. “There’s still a little bit of freezing rain in parts of New England. Most of it is either rain or snow at this point. It’s just foggy and drizzly in New York City, otherwise most of the precipitation is pretty light."

A vehicle involved in a crash sits on the fast lane of Highway Interstate 80 after an accident during a snowfall, Saturday, Dec. 17, 2016, in Lodi, N.J. Julio Cortez / AP

There will be some severe weather in parts of the South Saturday night, from Louisiana through Mississippi and up into Tennessee, forecasters said. It will likely consist of wind, hail and thunderstorms, but tornadoes are possible.

"It is snowing from Colorado to Iowa and Michigan, Wisconsin, Minnesota, and northern New York and most of New England north of Boston," said Houtz.