(CNN) -- A deep freeze will leave much of the nation shivering this weekend, making the nor'easter that just blanketed about 20 states with snow look like a mere curtain raiser.
Get ready for bone-chilling cold you haven't endured in years, the National Weather Service said.
Nearly half the nation -- 140 million people -- will shiver under zero degrees Fahrenheit or lower by Wednesday.
An arctic blast that drove the mercury to near minus 40 in parts of Canada is roaring into the United States.
It is threatening to sweep subzero lows as far south as Alabama, and plunge much of the Deep South into the teens.
The blast burst onto stage in the northern Plains States early Saturday, pushing out previous highs in the 40s and 50s. It hurled North Dakota into minus territory, as the weather service predicted a day-long blizzard for the state.
Parts of Montana and Minnesota were feeling the same pain, the NWS said.
If there was ever a winter-toughened state, it's Minnesota, but with this frosty bite on its way, schools in the state are shutting their doors on Monday.
"I have made this decision to protect all our children from the dangerously cold temperatures," Minnesota Gov. Mark Dayton said.
Saturday's temperatures will look spring-like a day later, as the thermometer falls to near -30 in parts of North Dakota. And the wind will drive chills down to -50 degrees, the weather service said.
That's a recipe for rapid frost bite or hypothermia.
A man age 66 died Friday of hypothermia in Milwaukee, Wisconsin, on Friday, the medical examiner's office said.
The weather service's Twin Cities, Minnesota, division warns, "Exposed flesh can freeze in as little as five minutes with wind chills colder than 50 below."
This system will produce "the coldest air in two decades," the service said.
The danger of injury and death from the cold will spread with the cold front into the Midwest by Monday night.
Sunday night in Chicago will see a shivering minus 16 to 20 below and -- once you factor in the Windy City's stiff breeze -- a chill of 35 below to 45 below zero.
Lambeau Field in Green Bay, Wisconsin, is unfortunately not a domed stadium. Fans and players there will sit outdoors and brave temperatures approaching minus 20, as the Packers battle the San Francisco 49ers for a chance to advance to the Super Bowl.
Some sports writers speculated that it may go down as the coldest football game ever played.
The Packers organization and a stadium vending company will serve free hot chocolate and coffee to help fans withstand the deep freeze, as wind chills dip to 50 below.
As Packers head coach Mike McCarthy said Friday: "This is not the norm."
As the arctic cold conquers about half of the continental United States, temperatures are forecast to dip into the minus teens through the lower Midwest. Snow will cover swaths from the plains to the Ohio and Mississippi River valleys all the way to New England.
Parts of the Midwest could see temperatures not recorded in 15 to 20 years -- for a painful couple of days.
Even areas as far south as Nashville, Tennessee, could be frozen solid in zero-degree cold as the arctic air mass dives southward at the beginning of next week.
Thousands were stuck at airports nationwide Friday because of system-wide delays -- though at least they not out in the frigid cold.
FlightAware.com, which tracks cancellations due to weather and mechanical problems, said about 3,200 flights were canceled Friday within, into or out of the United States.
Expect more of the same in the coming days. Long before sunup Saturday, over 500 flights were struck with half as many delayed.
Though the temperature in Las Vegas was 52 degrees -- above zero -- passengers there were also feeling the winter's sting Friday.
Long lines formed inside McCarran International Airport at the counters for Southwest Airlines, which had canceled many of its flights to and from Chicago. The airline carries 40% of Las Vegas' passengers, according to Chris Hayes, an airport spokesman.
Insane snow that was
It's not like those who braved the last storm would have it easy, even if more snow was not on the way.
Just ask Ford Fischer. The CNN iReporter spent part of Friday trying to clear the driveway around his home in Boxford, Massachusetts, where the weather service said more snow -- 23.8 inches -- fell than in any other community hit by the Thursday-into-Friday nor'easter.
Every time he finished a spot, he'd turn around and see it covered with snow again.
"The snow was absolutely insane," Fischer said, "and totally nonstop."
Even after the snow was done, the bottom dropped out of the temperature.
In parts of New York City, where as much as 8 inches
of snow fell, the mercury dropped to near zero Friday night for the first time since January 1994.
It was also set to dip below zero, with minus 17 wind chill, in Boston after nearly 18 inches of snow.
Outages not as widespread
Power outages were not as widespread despite blizzard-level winds in some places when the nor'easter passed through in previous days.
Three people died in car accidents in Pennsylvania -- including one man crushed as he was moving street salt with a forklift.
A car accident in icy conditions in Indiana killed one person Tuesday, authorities said.
In Byron, New York, a 71-year-old woman was found dead in the cold weather, authorities said.
And in Torrington, Connecticut, a man died in a weather-related car accident Friday.
CNN's Joe Sutton contributed to this report.
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