At least 14 people are dead so far. Schools closed across the country. 4,400 flights canceled. Many businesses at a standstill. All the result of a pool of cold air known as a polar vortex, bringing... See More
At least 14 people are dead so far. Schools closed across the country. 4,400 flights canceled. Many businesses at a standstill. All the result of a pool of cold air known as a polar vortex, bringing with it the coldest chill in decades. Abc's gia benitez is out in the frozen zone where fire departments, hospitals, and the ships that carry our precious goods are struggling to survive the cold. Reporter: Michigan's upper peninsula. A lifeline to a frozen nation. Here the extreme chill could have disastrous results. The major shipping routes separating the u.S. And canada is where heating oil, coal, and so much else must pass. And there are now just precious days left to get the big ships through. A race against time. This is the kind of stuff that we're breaking through right now. That ice is a foot thick. Reporter: And that's just very difficult ice to break through because when it knits together it knits together stronger than it did before. My name is lieutenant commander john henry. Currently on coast guard cutter bristol bay heading down down in the st. Marie's river system. Reporter: One of the cutters smashing through these waters around the clock. There's no way you can stop in this sound. Icebreaking is a very loud job. If you get a strong wind it will blow the track that you've spent so much time building. It will just blow it out of the channel. And then you're left with brand new plates trying to work through stuff like this on the side and creating a brand new track. Reporter: Hundreds of miles south where the cargo is crucial chicago is bracing for the lowest temperatures on record. It's minus 13 at o'hare right now. Minus 11 at the lakefront. Wind chill minus 40 below. Reporter: Our day starts on the city streets, where the deep freeze is causing a nightmare on the roads. Aaa reporting thousands of calls for help. Some for collisions like we saw this weekend in colorado. But about a third for car battery failures. So we hit the road with a pro. All right. So let's get out there. Reporter: Tow truck driver james rogers. Fluids freeze. It's just hard to maintain a car in this type of weather. Everything just freezes in the car. Frozen, cold. Could be for the battery, not getting the spark from your starter. A lot of people are getting stuck. How many cars do you think you've done in the past week? 60, 70 cars. And just last night? 25, 30 people. It's just so cold that there's barely any guys on the street helping out. Reporter: Within ten minutes at 11:00 a.M. A driver waves us down. Are you guys a towing company? Yes, sir, towing. Can you open cars? Reporter: He had just helped another driver get out of the snow and got locked out of his own car. You think your handle got frozen and it just snapped. Reporter: This winter freeze falling hard on some of chicago's most vulnerable. Stay warm and stay safe, huh? I'm just going to lift this up, okay? Reporter: At cook county hospital doctors are bracing for patients suffering from exposure. How are your feet feeling right now? Are they better? Yeah. Not only are we experiencing problems with cold injury and direct impact to the skin, but everything tends to get worse. People have lack of access to their medicines. They can't get to their appointments. So their problems that they already had are going to be getting worse. Reporter: Miguel ganis, a homeless man, came in with swollen feet. I'm very worried it could be frostbite. Reporter: It turns out miguel also has pneumonia. Absolutely. This brutally cold weather attributed to his illnesses getting worse. Reporter: But even safely inside his home, another chicagoan shows the world what it was like outside his window. Right now it's 20 below, which is the coldest it's been in about 20 years with the wind chill down to around 50 below. Reporter: In minneapolis schools are closed today and tomorrow, but they're ready for anything at fire house 8. We're engine 8. We're in the first district. Today we expect to see a lot of frostbite. Probably the biggest thing we'll see. Also frozen pipes are big on a day that's extremely cold like this. Reporter: Just before 1:00 p.M. A call comes in. Went on a medical run. Possible heart attack. Reporter: A 53-year-old complaining of heart trouble. Right in here. Okay? Bring the lady inside here. Come on in here. We'll get you warm until an ambulance comes. All right? Medication? Penicillin. Reporter: They keep him warm in the fire truck until an ambulance arrives to take him to the hospital. The guy was out walking around, possibly homeless. And we took care of him. High blood pressure. High heart rate. Got him on some o2. And got him out of the cold. Reporter: After the call they head back to the fire house and ready for any other emergencies that cold weather might bring. The weather was so harsh it even created a water spout out on lake superior. With that great lake behind it, the american mariner now hoping to push into the waters of the huron. You said the american mariner was coming through at 18:30. Oh, this will be interesting. Reporter: The "mariner" is a giant ship, more than two football fields long and able to carry 37,000 tons. Tonight she's trying to get to indiana. The biggest cargo for these lakers are iron ore, coal, heating owl, and grain. And they pretty much come and service all the great lakes. I mean come through the sault locks and headed down toward either lake erie or lake michigan. Reporter: But the "mariner" has had trouble in these waters before. Running aground, bringing shipping here to a halt before she was towed away. And that was in good weather. Just to get an idea of how close this actually is, about 80 yards off on our port side, our left side over here is six foot of water. There's not a lot of room to work with here. Reporter: With sunset less than two hours away, will it be safe? One of the biggest parts of being in this job is having to make that call. This is news radio 620, wtmj. At 2:01 it's 13 degrees below zero. Reporter: In milwaukee we meet up with police officers from a special unit prowling the streets to save the especially vulnerable homeless. It's extremely cold, and people could get frostbite, and they could eventually die out here. You want to go somewhere right now warm.Library's open till 6:00. It's nice to know that there is somebody out there looking out for the people that are like myself. Put these on, man. We'll look for you later on tonight. Okay? Okay, then. All right, eddie. Stay warm. Okay. Reporter: Back here in chicago the city hit a new record low of 15 degrees below zero at o'hare international airport. The cancellation of more than 1,600 flights left thousands of passengers stranded, causing long lines that made travelers appear, well, frozen. I think it's about 20 or 30 below zero. Reporter: Lost luggage piled up. And the frustration piled on. So what's behind this cold spell? Some scientists say it's actually tied into global warming. The sea ice in the arctic is changing. And that's changing the temperature difference, which changes the patterns of weather we see here. It's just a general disruption of the rhythm and patterns of the chaos that is our weather. Reporter: Back on the river connecting lake superior and huron the coast guard is running into some of the toughest ice they've seen all day. And this is one of the things that I wish that the camera could capture, is the sensation that you're feeling right now is the entire ship is just shaking as she tries to cut through this cuff refrozen ice. And there she comes. Reporter: And now lieutenant commander henry and his bosses have a decision to make. Is it safe enough for the "american mariner" to pass? By the time they get down here, it will be dark trying to go through. I wouldn't feel comfortable trying to work that right now. That definitely will do. Thanks, sir. The plan hot off the presses, literally the phone call just came through. The american mariner will be holding through the night and doing the transit first thing in the morning. With a fresh set of eyes at sunrise we can do the transit down the tighter parts of the river. It's going to get cold. It's going to get uncomfortable. The ice is going to freeze. But that's what we were built for. That's why we're out here. Reporter: And with that the "bristol bay" and her crew head out again, ready to face a winter that's already smashing through the record books. For "nightline" I'm gio benitez in chicago.
This transcript has been automatically generated and may not be 100% accurate.