Icy eyebrows. Frosted eyeglasses. I'm wearing long underwear. I feel like I'm going skiing. But I'm not. I'm going to work. Reporter: To get a true sense of the arctic blast, one need only to let a... See More
Icy eyebrows. Frosted eyeglasses. I'm wearing long underwear. I feel like I'm going skiing. But I'm not. I'm going to work. Reporter: To get a true sense of the arctic blast, one need only to let a little of the outside in. On the streets, the bitter cold is dangerous. They could eventually die out here. Reporter: We road along with the milwaukee police officers, patrolling the streets and finding people who need a place to stay. I know the library's open until 6:00. Oh, yeah? Okay. We'll look for you later on tonight, okay? Okay, then. Eddie, stay warm. Okay. Reporter: Handing out hats and socks to those who need it most. In emergency rooms across the midwest tonight, frostbite, the top concern. With these temperatures, it can set in just five minutes. Not safe for anyone to be outside for any period of time. Reporter: Doctors say many frostbite victims, like this man in chicago, wait too long to get help. It wasn't only his feet that were the problem. He ends up having a pneumonia, as well. Reporter: Escaping this cold could be a matter of life or death. Alex perez, abc news, milwaukee. Our thanks to alex, gio and linzie. Back with us on the cold, abc's chief medical editor, dr. Richard besser. We think we're bundled up. But we're losing heat. In this temperature, you want to completely bundle up. We took a pictures with aer the mall camera. Look at this. The red, the heat coming off this man. You see his face and neck are giving off heat. Look closely. You can see where the zipper of his jacket is losing heat. If you lose too much heat and there's a real danger of hypother hypothermia. You need to wear thin layers. And where a scarf under that zipper and wool or synthetic fibers. Seal off the middle part of your body. And you have images showing how frostbite begins. Yeah. This man is standing outside. He takes off his gloves. Look what happens. The heat, that orange/yellow, over the course of one minute, it disappears. That's the beginning of frostbite. His fingers losing all heat. His body is protecting himself and keeping his heat in his core for his essential organs. You can't have exposed skin in this weather. Thank you, rich besser. And next, big news, tonight, from overseas.
This transcript has been automatically generated and may not be 100% accurate.