Polar vortex brings coldest air in a generation

An Arctic front is about to deliver a burst of snow, extreme winds and rapidly falling temperatures to Washington, DC, and Baltimore, Maryland.

Winds gusts of up to 50 mph will accompany the snow over the next couple of hours. 

There won't be much snow: Only about an inch of accumulations are expected. But combination of the snowfall and gusty winds will create greatly reduced visibility and will likely cause travel trouble on the roads and at the DC airports.  

And a flash freeze is possible: Temperatures behind the front will quickly drop by 10 degrees in less than 30 minutes. This will cause a flash freeze of any untreated wet roads, sidewalks and parking lots.

Temperatures will continue to fall to around 20 degrees by 6 p.m. ET.

Amtrak canceled all service to and from Chicago on Wednesday due to the frigid temperatures.

Short-distance trains and long-distance overnight trains were also put on hold.

Amtrak said it typically operates 55 trains daily to and from the Chicago hub.

It's currently -18 degrees in Chicago (and with the windchill it feels like -45).

But the good news is things will warm up — and they're going to warm up fast.

By Sunday, Chicago could reach 40 degrees, with rain in the forecast. That's almost 60 degrees warmer than it is right now. Balmy!

And what about the Super Bowl? Atlanta will see temperatures in the low 60s for the big game on Sunday.

The freeze gripping the Midwest and Northeast peaked this morning, around 7 a.m. ET., and approximately four of every five Americans felt the chill.

At the time the freeze peaked, around 80% of the country was experiencing below freezing temperatures. That's more than 224 million people.

Also at that time, around 20% of the country was below zero -- about 60 million people. And, at the extremes, nearly 10% of the country was colder than 20 degrees below zero, or just over 25 million people.

The good news? 48 days until spring.

The American Red Cross says the winter weather has led to the cancellation of 370 blood drives across the country, with more than 11,500 blood donations going uncollected this month.

Anyone not impacted can make an appointment by using the Blood Donor App, visiting RedCrossBlood.org or calling 1-800-RED CROSS (1-800-733-2767).

At least five deaths have been linked to the extreme snow and weather:

There were seven racers left this morning in the 135-mile race in Minnesota. Since then, one has dropped out and two have finished according to Arrowhead 135 race officials.

That leaves four racers on the course, still battling the horrific temperatures.

It's insanely cold out there: Temperature at the finish line has risen a bit to -31 degrees (it was -35 this morning). The windchill is still -52.

More about the race: Runners start in International Falls, Minnesota, and make a 135-mile slog to the finish at the Fortune Bay Casino in Tower, Minnesota. They can either run, bike, ski or kick sled.

They're equipped with mandatory survival gear and are encouraged to self-rescue —there's only three checkpoints in the race. Krueger says only one racer has quit because of frostbite.  

Today is the final day of the race; participants have until 7:00 p.m. to finish.

To track the participants progress, click here.

So far today, 2,190 flights into, out of and within the US have been canceled, according to FlightAware.

Another 1,125 US flights have been delayed.

Right now, the most delays are at Chicago's O'Hare International Airport:

New York City Emergency Management warned of dangerous travel conditions during tonight's evening commute.

According to the National Weather Service, an "intense burst of moderate to heavy blowing snow" is expected to blow through New York City this afternoon.

"This intense burst of snowfall combined with strong wind gusts may cause brief whiteout conditions, limiting visibility and making travel extremely dangerous," the emergency office said in a statement.

New York officials are urging commuters to...

Read more from NYC Emergency Management: