(CNN) Blasts of cold air mixed with freezing rain have created treacherous road conditions throughout the United States over the weekend, causing multiple-car pileups and fatalities.

At least six people died in Virginia, Maryland and Oklahoma because of the dangerous road conditions, authorities said.

A 55-vehicle crash on a icy stretch of Interstate 95 in Baltimore, Maryland left at least two people dead and motorists stranded for hours about 5 a.m. Saturday, according to Chief Roman Clark, a Baltimore Fire Department spokesman. Fifteen people were taken to hospitals.

A video posted on social media showed a fuel truck flipping over a median on the interstate near the Washington Boulevard exit before erupting in flames. A man is heard asking, "What is going on?" as flames and dark smoke rise from under the highway.

Baltimore Mayor Catherine Pugh said good Samaritans helped pull people out of cars.

"This is the worst accident that we've seen," she said.

Emergency vehicles descended on the scene, stalling traffic for miles and leading authorities to urge stranded motorists on both sides of the interstate to "remain warm and calm and shelter in place" in their cars, Clark said.

The cause was under investigation, but Clark described road conditions as "very slippery."

In northern Virginia, authorities responded to more than 40 traffic accidents, some involving multiple vehicles, according to the state police.

One person was killed after a multi-vehicle crash at 5:12 a.m., Saturday, on Interstate 495 in Fairfax County, police said.

The man appeared to have been involved in a 23-vehicle collision -- including two tractor trailers -- under "slick and treacherous" road conditions, according to the state police. His body was found on the shoulder of the interstate about one mile north of the accident scene. An autopsy was to be performed.

On Thursday, three people were killed in weather-related accidents around Oklahoma City, the Oklahoma Highway Patrol reported.

At Dulles International Airport, just outside Washington, D.C., icy conditions forced the closure of runways for part of the morning. Two runways were reopened about 11 a.m. Saturday.

Nationally, there were 2,000 flight cancellations, according to FlightAware.

The brutal blast of frigid air is bringing bone-chilling winds and subfreezing temperatures across the country this weekend.

The National Weather Service warns that the massive system will produce heavy snow from parts of northern California to the Great Lakes.

Its reach will extend into the southern Rockies and New England.

Here's what you can expect:
• Nearly 50% of the country will see temperatures dip below freezing Saturday and Sunday.
• With the wind chill, temperatures could reach 35 below zero in the Midwest and Northeast on Saturday.
• Nearly 75 million people are under winter weather advisories

Arctic air plunging in behind a cold front is making its way across the Eastern Seaboard on Sunday morning, according to meteorologists.

Bitterly cold temperatures and dangerous windshield factors swept across Montana to Texas through the Great Lakes.

Potentially life threatening wind chills as low as 50 degrees below zero are expected in North Dakota, South Dakota, Montana, Colorado and Idaho.

Portions of Illinois, Wisconsin and Minnesota could get the coldest air the region has seen in two years.

New York, Washington and Boston had extremely cold temperatures Saturday, with the wind chill ranging from minus 10 to minus 35 degrees in some locations from Pennsylvania up into Maine.

Strong winds have already been an issue, with gusts in excess of 60 mph in some locations, including areas along Cape Cod.

A roller coaster ride of temperature swings are in store for parts of the country in the coming week.

Warm air is expected to surge into the Southeast, where it could meet with the storm system through much of Saturday as it crosses the Mississippi Valley. A wintry mix of rain and snow can be expected in parts of some areas that were close to freezing on Thursday evening in the deep South could see near-record highs ahead of the next push of bitter cold air.

But the respite may be brief as the next arctic blast is expected to impact areas stretching from the Plains into the western Great Lakes, causing temperatures to plummet below zero Sunday.

This weekend's game between the Chicago Bears and the Green Bay Packers could be the coldest since the Bears started tracking kickoff temperatures.

The previous record was set December 22, 2008 -- also against the Packers. The kickoff temperature was 2 degrees, with a frigid 13 below zero wind-chill temperature.

Chicago is poised to break that record Sunday.

The Buffalo Bills on Saturday made an appeal for snow shovelers at New Era Field in Orchard Park, New York. The pay is $10 an hour, plus lunch and dinner and a complimentary ticket for those working four hours or longer. The Bills play the Cleveland Browns Sunday afternoon.

Rain, wind, and snow are also impacting a majority of California from this new round of weather that has moved in from the Pacific. Some areas have seen more than seven inches of rain with wind gusts in excess of 50 mph.

Upcoming western coastal storms will usher in frost and freeze warnings in California along with gusty wind and mountain snowfall Saturday. Officials also are concerned about possible mudslides, triggered sometimes when heavy rain hits drought-stricken areas. </s> (CNN) A brutal blast of frigid air sweeping across the United States wreaked havoc on roads in Virginia and Maryland, leaving at least three dead in multi-vehicle wrecks Saturday, authorities said.

A 55-vehicle crash on a icy stretch of I-95 in Baltimore left at least two people dead and motorists stranded for hours about 5 a.m. Saturday, according to Chief Roman Clark, a Baltimore Fire Department spokesman. Fifteen people were taken to hospitals.

A video posted on social media showed a fuel truck flipping over a median on the interstate near the Washington Boulevard exit before erupting in flames, CNN affiliate WBAL reported. Clark confirmed the video showed the I-95 crash.

[GRAPHIC] This is video of a fuel tanker sliding over the rail on I-95 this AM and EXPLODING shortly after. (via Marvellous Amasiacu) #WBAL pic.twitter.com/A49YrqNn89

Baltimore Mayor Catherine Pugh said good Samaritans helped pull people out of cars.

95 in Baltimore .Multivehicle accident. Roads are extremely icy. I guess they forgot the treat the roads. #winter2016 #baltimore @fox5dc pic.twitter.com/tbCsKa8ulC

"This is the worst accident that we've seen," she said.

Emergency vehicles descended on the scene, stalling traffic for miles and leading authorities to urge stranded motorists on both sides of the interstate to "remain warm and calm and shelter in place" in their cars, Clark said.

The cause of the wreck was under investigation but Clark described road conditions as "very slippery."

In northern Virginia, authorities responded to more than 40 traffic accidents, some involving multiple vehicles, according to the state police.

One person was killed after a multi-vehicle crash at 5:12 a.m. on Interstate 495 in Fairfax County, state police said.

The man appeared to have been involved in a 23-vehicle collision -- including two tractor trailers -- under "slick and treacherous" road conditions, according to the state police. His body was found on the shoulder of the interstate about one mile north of the accident scene. An autopsy was to be performed.

At Dulles Airport, just outside Washington D.C., icy conditions forced the closure of runways for part of the morning. Two runways were reopened about 11 a.m.

Nationally, there were 1,870 flight cancellations, according to FlightAware.

The dangerous conditions arrived as some people started their holiday travel early.

"If you don't have to go out on the roads, we would ask that you just stay in at this time until the temperatures rise," Clark told CNN.

In Indiana, the Wayne Township Fire Department and the Indianapolis police used a ladder to evacuate stranded drivers from I-465.

Police in Marion and Hendricks counties responded to nearly 200 accidents, 36 involving injuries, between 10 p.m. and 4 a.m., according to the Indianapolis police.

In northwest Missouri, I-29 reopened to traffic Saturday after dozens of drivers were trapped in their cars the night before, CNN affiliate KQTV reported.

The frigid air blast is bringing bone-chilling winds and subfreezing temperatures to millions across the country this weekend.

The National Weather Service warns that the massive system will produce heavy snow from parts of northern California to the Great Lakes.

Its reach will extend into the southern Rockies and New England by Saturday.

Here's what you can expect:
• Nearly 50% of the country will see temperatures dip below freezing Saturday and Sunday
• With the wind chill, temperatures could reach 35 below zero in the Midwest and Northeast on Saturday

Major coastal cities in the Northeast will see a changeover from snow to rain by Saturday evening.

A strong storm over the central Rockies will move northeast to New England by Sunday morning.

Potentially life threatening wind chills as low as 50 degrees below zero are expected in North Dakota, South Dakota, Montana, Colorado and Idaho.

Portions of Illinois, Wisconsin and Minnesota could get the coldest air the region has seen in two years.

New York, Washington and Boston had extremely cold temperatures Saturday, with the wind chill ranging from minus 10 to minus 35 degrees in some locations from Pennsylvania up into Maine.

Strong winds have already been an issue, with gusts in excess of 60 mph in some locations, including areas along Cape Cod.

A roller coaster ride of temperature swings are in store for the next week.

Warm air is expected to surge into the Southeast, where it could meet with the storm system through much of Saturday as it crosses the Mississippi Valley. A wintry mix of rain and snow can be expected in parts of Some areas that were close to freezing on Thursday evening in the deep South could see near-record highs ahead of the next push of bitter cold air.

Houston could break a record high temperature on Saturday of 81 degrees.

But the respite may be brief as the next arctic blast is expected to impact areas stretching from the Plains into the western Great Lakes, causing temperatures to plummet below zero Sunday.

This weekend's game between the Chicago Bears and the Green Bay Packers could be the coldest since the Bears started tracking kickoff temperatures.

The previous record was set December 22, 2008 -- also against the Packers. The kickoff temperature was 2 degrees, with a frigid 13 below zero wind-chill temperature.

Chicago is poised to break that record Sunday.

The Buffalo Bills on Saturday made an appeal for snow shovelers at New Era Field in Orchard Park, New York. The pay is $10 an hour, plus lunch and dinner and a complimentary ticket for those working four hours or longer. The Bills play the Cleveland Browns Sunday afternoon.

Rain, wind, and snow are also impacting a majority of California from this new round of weather that has moved in from the Pacific. Some areas have seen more than seven inches of rain with wind gusts in excess of 50 mph.

Upcoming western coastal storms will usher in Frost and Freeze warnings in California along with gusty wind and mountain snowfall Saturday. Officials also are concerned about possible mudslides, triggered sometimes when heavy rain hits drought-stricken areas.

As millions of people take to the roads over the holiday weekend, snow and ice will make for dangerous driving conditions on the roadways, the National Weather Service warns.

Drivers in Raleigh, North Carolina have been advised to stay home and avoid travel due to the inclement conditions.

"Freezing rain is causing traffic-related issues throughout Raleigh at this hour," the Raleigh Police Department said in a memo Saturday.

"As is typically the case, bridges and overpasses were the among the first areas to have issues due to icing, but the problems are widespread and not limited to those locations." </s> A blast of cold air caused rain and wet roads to freeze across the Eastern U.S., triggering airport delays in the nation’s capital and major traffic pileups in Maryland, Virginia and North Carolina. Authorities say two people were killed in a chain-reaction accident in Baltimore involving a tanker carrying gasoline that skidded off a highway and exploded.

Baltimore City Fire Chief Roman Clark said two people were killed and at least 15 were injured in the 55-vehicle accident and tanker explosion on Interstate-95. Clark said the tanker careened off the highway, fell over a jersey wall and burst into flames.

Clark said it’s too early to say whether the crash was caused by slick roads, although scores of traffic accidents were being reported across the region due to icy roads.

“The roads were very icy,” Clark said. “We have nothing but sheets of ice throughout the city, sidewalks,” he said.

Officials have not released the names of the two people killed in the crash. Clark said it’s unclear whether the pileup started before the tanker crash or was caused by the incident.

Earlier Saturday, Bob Maloney of the Baltimore City Office of Emergency Management was quoted by WBAL-TV as saying that at least 30 cars were involved in an accident on northbound I-95.

Baltimore County said on Twitter that between 15 and 20 vehicles were involved in a crash on I-695 near Rosedale. Six people were taken to the hospital.

The National Weather Service has issued a wintry weather advisory for the Baltimore area, meaning that periods of sleet and freezing rain through noon will lead to slippery roads and limited visibility.

In Virginia, meanwhile, State Police say 41 traffic crashes were reported in the northern part of the state. It was unclear how many were due to slick roads. One fatality was reported.

Authorities in Ohio say a Columbus woman was killed Saturday after her car skidded off a slick road.

Two airports serving the nation’s capital are experiencing delays or cancellations Saturday.

Washington Dulles International airport reopened two runways after having to close all runways for more than three hours due to icy weather. Wintry weather forced the airport to halt all flights early Saturday. The airport says two runways reopened for flights as of 10 a.m., but that travels should expect residual cancelations and delays.

A spokesman for the Metropolitan Washington Airports Authority says Reagan Washington National Airport is operating normally, but some flights may be delayed or cancelled due to bad weather along the East coast.

A spokesman for Baltimore/Washington International Thurgood Marshall Airport says the weather is causing some delays and cancelations but no runways have been closed.

In central North Carolina, light freezing rain has caused scores of traffic accidents, adding to the road mayhem scattered throughout the Eastern U.S.

Police and emergency workers reported more than 100 crashes overnight Saturday in Raleigh and Charlotte as the drizzle combined with temperatures below freezing for approaching 40 hours combined to create dangerous icy patches.

Charlotte police reported two people dead in separate fatal crashes early Saturday, although investigators are still trying to figure out if ice caused the wrecks. </s> A winter storm of snow, freezing rain and bone-chilling temperatures socked the nation’s mid-section and East Coast on Saturday, causing hundreds of accidents on icy roads and putting a crimp on Christmas shopping.

At least six deaths were blamed on the slick roads and authorities were investigating a few other traffic fatalities as possibly weather-related. Perhaps the biggest accident happened in Baltimore, when a tanker carrying gasoline skidded off a highway and exploded, authorities said.

Two people died and at least 15 were injured in the 55-vehicle pileup on Interstate 95, Baltimore City Fire Chief Roman Clark said. He said it was too early to determine the cause of the crash.

“We have nothing but sheets of ice throughout the city, sidewalks,” Clark said.

It was unclear whether the pileup started before the tanker crash or was caused by it. The northbound lanes of I-95 were closed while crews cleaned up the mess.

Winter weather advisories were posted from Denver to Bangor, Maine. Airports reported hundreds of flight delays or cancellations, interstates and toll roads reduced speed limits and authorities urged drivers to use extreme caution.

There were dozens of crashes in Indiana – two of them involving fatalities – due to freezing rain and ice, officials said. It was not immediately clear how many people were killed. The roads were so slick that authorities had to move motorists stranded on an overpass with a ladder.

In Ohio, a Columbus woman died Saturday when her car skidded off a slick road, authorities said. In another accident in Baltimore, six people were taken to the hospital after a crash on I-695 involving 15 to 20 vehicles, Baltimore County tweeted. In Nebraska, Douglas County Sheriff’s deputies said one person was killed Friday night when his car slid off an icy road north of Omaha, hit a tree and burst into flames.

Temperatures plummeted and people braced for the cold. Temperatures in the Minneapolis-St. Paul area were expected to drop to minus-20 degrees overnight. People were advised to stay indoors for the weekend.

In Virginia, a Fairfax County firetruck slid off an icy road while responding to a crash, local news media reported. Meanwhile, more than three dozen crashes and a fatality were reported in the northern part of the state, authorities said.

In North Carolina, police and emergency workers reported more than 100 crashes overnight in Raleigh and Charlotte as the drizzle combined with temperatures below freezing to create dangerous icy patches.

Charlotte police reported two people killed in separate fatal crashes early Saturday, although investigators were still trying to figure out if ice caused the wrecks. </s> A winter storm of snow, freezing rain and bone-chilling temperatures socked the nation’s mid-section and East Coast on Saturday, causing hundreds of accidents on icy roads and putting a crimp on Christmas shopping.

At least nine deaths were blamed on the slick roads and authorities were investigating a few other traffic fatalities as possibly weather-related. Perhaps the biggest accident happened in Baltimore, when a tanker carrying gasoline skidded off a highway and exploded, authorities said.

Two people died in the nearly 70-vehicle pileup on Interstate 95, authorities said. Hospital officials said nearly two dozen people were treated for injuries including broken bones and head trauma.

Warning: The below video contains coarse language!

Baltimore City Fire Chief Roman Clark said it was too early to determine the cause of the crash.

It was unclear whether the pileup started before the tanker crash or was caused by it. The northbound lanes of I-95 were closed while crews cleaned up the mess.

Winter weather advisories were posted from Denver to Bangor, Maine. Airports reported hundreds of flight delays or cancellations, interstates and toll roads reduced speed limits and authorities urged drivers to use extreme caution.

The nasty weather put a damper on holiday plans for Luke Perez, who was hoping to make it home to Los Angeles on Saturday for a family party. Perez’s flight out of D.C., where he is in graduate school, was cancelled, so he said he’s going to try again Sunday or Monday.

“My family has a Christmas party ... and I was hoping to make it to that tonight, but that’s not going to happen anymore,” the 23-year-old said.

There were dozens of crashes in Indiana — two of them involving fatalities — due to freezing rain and ice, officials said. It was not immediately clear how many people were killed. The roads were so slick that authorities had to move motorists stranded on an overpass with a ladder.

In Ohio, a Columbus woman died Saturday when her car skidded off a slick road, authorities said. In another accident in Baltimore, six people were taken to the hospital after a crash on I-695 involving 15 to 20 vehicles, Baltimore County tweeted. In Nebraska, Douglas County Sheriff’s deputies said one person was killed Friday night when his car slid off an icy road north of Omaha, hit a tree and burst into flames.

Temperatures plummeted and people braced for the cold. Temperatures in the Minneapolis-St. Paul area were expected to drop to minus-20 degrees overnight. People were advised to stay indoors for the weekend. The low temperature was expected to reach 4 degrees in Chicago on Sunday.

Portions of six states, from Missouri to Mississippi, were under the threat of tornadoes or severe thunderstorms.

In Virginia, a Fairfax County fire truck slid off an icy road while responding to a crash, local news media reported. No one was injured.

Meanwhile, more than three dozen crashes and a fatality were reported in the northern part of the state, authorities said. Police said a man was found dead on the side of I-495, about a mile from a 23-vehicle crash. It appears the man was involved in the crash and had walked away from disabled vehicle. It wasn’t immediately clear how the man died.

At least three highway deaths Friday in Missouri are being blamed on icy conditions. The Missouri State Highway Patrol crash reports ay a 13-year-old girl died from injuries suffered in an accident when a tractor-trailer lost control on ice on Interstate 44, striking a Jeep Renegade driven by the girl’s mother. Reports say two men, ages 72 and 56, died in separate accidents when the vehicles they were in went out of control on ice.

In Colorado, up to a foot of snow fell in places, snarling traffic. Even weather-hardened locals apparently had trouble driving.

“I worked for the fire department for 45 years, and we used to call this highway hockey because people keep bumping into each other,” said Kevin Sweeney, of Brighton, a town about 20 miles northeast of Denver. “I think it’s that first big snow thing.”

In North Carolina, police and emergency workers reported more than 100 crashes overnight in Raleigh and Charlotte as the drizzle combined with temperatures below freezing to create dangerous icy patches.

Charlotte police reported two people killed in separate fatal crashes early Saturday, although investigators were still trying to figure out if ice caused the wrecks.

Associated Press writer Steven K. Paulson in Denver contributed to this report. </s> The accident on Interstate 95, which occurred at about 5 a.m., left two people dead, including the driver of the fuel truck, said Lieutenant Kevin Ayd, spokesman for the Maryland Transportation Authority Police.

The fiery pileup was one of dozens of crashes in the Baltimore-Washington area as freezing rain slowly accumulated into an icy sheet on roadways in the early morning darkness.

A second multi-vehicle crash occurred at about the same time along Interstate 95 in Baltimore, part of a major north-south corridor along the U.S. East Coast. One person was killed in that accident when one of the drivers exited his vehicle and was struck by oncoming traffic.

In the 55-vehicle pileup, a bystander's video shows the skidding fuel truck hitting a barrier and flipping over in a gap between the north and southbound lanes. As the fireball spread, approaching cars and trucks can be seen attempting to stop but instead plowing into one another.

"I want to share my deepest condolences to those affected by this morning's multi-vehicle crash," Baltimore Mayor Catherine Pugh said in a statement. "Today's icy road conditions remind us all that it is imperative to exercise extreme caution due to severe weather."

The crash forced the closure of the northbound lanes on the highway. Photos posted online showed dozens of emergency vehicles and tow trucks on the scene.

"We do not know when I-95 will be reopened," Ayd said. "We urged motorist to stay off the road until conditions improve."

A winter weather advisory was in effect for the Baltimore-Washington, D.C., area until noon, according to the National Weather Service, as snow and freezing rain gave way to a wintry mix or rain across much of the Eastern Seaboard.

The NWS said at 10 a.m. that the heaviest weather had moved into the mid-Atlantic and Northeast, while the Upper Midwest and Great Lakes regions continued to see a mix of precipitation.

Warnings and advisories remained in effect throughout much of the country, stretching from the central Rocky Mountains to the East Coast. Dangerously cold conditions, in part due to high winds, were still being reported in the central plains and the Mississippi Valley. </s> BOLOGNA, Italy - At least two people were killed and 70 injured in a tanker truck explosion near Bologna, Italy.

The explosion happened on a busy highway and caused part of the raised roadway to collapse, CBS News reported.

According to CBS, video showed the tanker rear-ending a vehicle on the highway and causing an explosion. It was then hit by another vehicle from behind.

An unspecified amount of time later, a much larger explosion occurred. </s> MILAN — A tanker truck carrying a highly flammable gas exploded Monday after rear-ending a stopped truck on a crowded highway near the northern Italian city of Bologna. At least two people were killed, up to 70 injured and part of the raised expressway collapsed in the fireball.

Police said the accident and subsequent fire and explosion left some of the injured with severe burns. It also shut down a highway that is a key route between northern Italy and the Adriatic Coast and other points south, including Florence and Rome, the capital.

A police video showed the tanker failing to slow down quick enough and plowing into the rear of a truck stopped in traffic, with flames exploding on impact. Another truck appeared to hit the tanker from behind. After an unspecified time lapse, during which the highway was cleared of most other vehicles, the truck erupted in a second, enormous explosion that spanned eight lanes of the highway and beyond.

Flames shot up into the air, followed by a thick black cloud of smoke. Aerial photos showed a gaping hole left in the raised highway. TV images hours after the flames were doused showed the burned-out skeletons of hulking tractor trailers.

Italian prosecutors said the tanker was filled with liquefied petroleum gas, otherwise known as propane, used as a fuel in heaters, cooking equipment and vehicles.

Firefighters said the extreme heat of the flames caused the raised roadway to collapse, sending a heat explosion that incinerated dozens of automobiles on new car lots nearby.

In a separate vehicle accident in the southern Italian region of Puglia, 12 farm workers were killed Monday when the van they were traveling in collided with a truck and overturned, ANSA reported.

The accident was similar to one on Saturday, when a truck laden with tomatoes crashed into a van and four migrants died.

Colleen Barry is an Associated Press writer. </s> Two people have died in a huge explosion at a gas station in Italy.

Among the victims was a firefighter, the fire brigade in the town of Fara in Sabina near Rome tweeted on Wednesday.

At least 17 people have been injured, according to news agency ANSA.

A tanker caught fire for unknown reasons. The force of the resulting explosion had catapulted a tanker and a vehicle from the fire brigade several meters, the newspaper La Repubblica reported.

The site of the explosion is located about 50 kilometres north-east of Rome in the province of Rieti.

"The situation is under control," Fara in Sabina Mayor Davide Basilicata wrote in the early evening on Facebook.

The site of the accident was still inaccessible and traffic was being redirected.
Two people are killed and at least 15 are hospitalized following a 55-vehicle accident, involving a gas tanker explosion, on Interstate 95 in Baltimore, Maryland, as cold air causes rain and wet roads to freeze across the Eastern U.S. Three other deaths are reported from other accidents in the Baltimore-Washington, D.C. area. At least six people have been killed in total on icy roads.