Highs Friday were in the single digits, and often felt well below zero thanks to wind chills.
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Snow also began Friday afternoon and evening. Anywhere from a dusting to about an inch fell depending on where you are, but because it's so cold it will stick to everything, including sidewalks and roadways. Drivers and pedestrians should be careful and wary of slick spots.
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Temperatures will dip below zero once again overnight into Saturday, and highs in the teens are expected this weekend. Monday will see a brief respite with highs near 30 and then a blast of truly freezing air returns Tuesday. Wind chills Tuesday could dip as low as -50 degrees.
With wind chills that cold, bundling up properly can be a matter of survival. Areas that are most susceptible like fingers, toes, the tip of the nose and the ears, should be covered in weather this cold.
As temperatures dropped further as the sun went down, many opted to say, and eat, in. At Opart Thai in West Town, phones ran off the hook and online orders came in constantly, keeping the staff running to keep up.
"We'll probably do 300 covers by the end of the night," said Rush Ponchuo, Opart Thai.
The in-house delivery driver headed out with a full load, and other delivery services made pick-ups as well.
"Sometimes we do subcontract to other drivers just when it's this busy to help us with delivery," Ponchuo said.
"I'll probably go 'til about 3:30 in the morning," said Keith Schmoeller, Door Dash delivery driver.
But it can be rough out there. Side streets and their adjoining sidewalks are still mostly snow-covered, on top of ice left from earlier this week.
"You have to be careful when you're crossing the street because there's a lot of ice out there," Schmoeller said.
"Slippery. They could definitely use more salt or sand or something," said Stef Andrews, resident.
Areas of the city are still covered with ice. For those who work outside in the cold, like internet installer Eric Kocka, bundling up and staying hydrated are necessary for survival.
"Layers and water," Kocka said. "If you don't drink water you're going to be in trouble. And you're not thirsty because it's freezing."
While residents bundled up, the frigid temperatures did cause some problems. Many had difficulty navigating icy sidewalks near vacant lots and abandoned homes. Gordon's Ace Hardware Store on Orleans Street said bags of ice melt are going fast as people try to get rid of the ice before more snow falls.
"We've actually sold quite a bit so far," said Assistant Manager Brian Wolff. "We actually had a pallet go out the other day."
During the frigid morning commute gates at six different crossings along a mile and a half stretch near the LaGrange and Brookfield border came down and wouldn't go back up, forcing the BNSF line to Aurora, the busiest line to slow to a crawl. Meanwhile, drivers took chances, speeding around the gates to get by.
Metra says a broken rail, likely brittle from the cold may have fractured sending the gates down for safety.
Some folks chose to embrace the season, heading over to Millennium Park to enjoy some skating.
"It's 5 degrees outside, but I enjoy ice skating," said Liz, a skater who asked we only use first name. "It's the winter, so Chicago is cold.
While Chicago and cold weather are synonymous, a rare few like Olympic ski jumper Mike Glasder actually enjoy it.
Glasder returned home this weekend to compete at Norge Ski Club's 115-year-old ski jumping tournament in Fox River Grove.
"There's going to be a couple thousand people here, super exciting to see all these athletes from around the world fly through the air. We love it, to have all the crowd cheering for us, it's an awesome atmosphere," he said.
Glasder, 28 of Cary, Kevin Bickner, 21 of Wauconda, and Casey Larson, 19 of Barrington, all competed but fell short of medals. However, their accomplishments were inspiring to 45 kids who signed up for lessons this season.
Watching ski jumping is one of several activities at Norge this weekend. There's also sledding, bonfires, and hot cocoa - and for parents, a bar.
"We're cold weather people so we love toe warmers and hand warmers, but again, if you stay active you gotta keep an eye on it. Please come out, we'll have space heaters around, fire pits, lots of food and drink, come out and have a blast," said Guy Larson, coach at Norge Ski Lodge. "We have kids as young as 3-years-old, all the way up to teens, anyone is welcome to come out."
Thick layers are the key for any outdoor activities. Doctors say at these temperatures it takes only 10 to 15 minutes to get frostbite. Whether you're a skier or not, at Norge they have all the answer on what to wear this season.
"Long johns, a couple pairs of socks, wool socks if you need to, long Under Amor, and you can go ahead and throw in another long sleeve under that and a hoodie and a shell and another coat. That's how I do it. It's better to be layered up you'll always be able to take a layer off if it's too much for ya," said Lucas Gasienica.
Of course, you could ditch the layers and move indoors for activities like laser tag. Just down the road from Norge is the Battle House indoor laser tag facility.
"We have 15,000 square foot arena with eight two-story buildings, a real crashed helicopter and more," said Alexandra Loppnow, general manager of Battle House Tactical Laser Tag. "If you love playing videos games this is a great way to be active while avoiding the cold."
TRANSIT AGENCIES, IDOT PREPARED FOR COLD WEATHER
Despite dealing with freezing switches in some areas, a few rail breaks and some mechanical failures, Metra said it had some residual delays but kept things moving and to prevent issues crews have been using fire to heat up parts of the tracks to keep the metal from contracting.
Metra sad it will keep traffic off of that one track that has the break so they can fully repair it. However Metra expects this cold spell to wreak a lot of havoc.
Metra said it now has signal crews on 12-hour shifts around the clock so that someone is always available. In the train yards Metra will have extra personnel because it will not shut off its locomotives over the weekend.
During the extreme cold, the Illinois Tollway launched around-the-clock road patrols so they can quickly help any stranded drivers and respond immediately to calls that come in to *999 motorist assistance.
To stay safe in these extreme cold, the Tollway recommends that you have your cell phone fully charged before heading out, be sure tires are properly inflated, keep your gas tank at least half full to avoid gas line freeze-up and keep a cold weather safety kit in your car, Items like a flare, blanket and flashlight.
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AAA is ready to respond to hundreds of phone calls from people in need of roadside assistance
"If you're heading out today make sure your gas tank is full so it can keep you warm if you're stuck and make sure you have plenty of warm gear in the car with you," AAA spokeswoman Beth Mosher.
Mechanic Chris Barrett of Chippers Auto Care in Darien said the negative temperatures are hard on your vehicle, especially your tires.
"Mainly it is tires," Barrett said. "No matter what you do, the tires are going to lose air."
A surge of arctic air is blasting into Chicago and the Midwest, starting this week and continuing into February. The Polar Vortex, which gained notoriety in 2014 when it brought shockingly cold temperatures to the Midwest, is a circulation of cold air in the Arctic Circle about 7 to 10 miles above ground in the stratosphere.
The vortex's strong circulation usually keeps it up above the North Pole, but when it weakens little pieces of energy break off and split, and send arctic air south.
The cold air then goes back to circling the North Pole in the summer.
The Associated Press contributed to this report.