But there are people who showed up for work today no matter the numbing cold. And they did it to help others. Abc's gio benitez has the heroes of the cold. Reporter: All across this frozen nation,... See More
But there are people who showed up for work today no matter the numbing cold. And they did it to help others. Abc's gio benitez has the heroes of the cold. Reporter: All across this frozen nation, workers like this michigan mailman, who has no other choice but to be outside in 15 degree cold. Today I'll be in the field about seven hours. Reporter: In new york, this delivery man, pushing packages of meat through the snow. In maryland, a postal worker climbing on the hood of his delivery truck to clear off ice. And here in chicago, where this morning we faced wind chills of 12 below zero, firefighters were called to a three alarm fire. Frigid temperatures freezing icicles on that fire hydrant. Most people can stay inside but your firefighters have to be out here in the cold. Well, it's icy cold conditions, or its hot conditions, either way, the firefighters, they have a battle in front of them. Reporter: The deep freeze closing schools in wisconsin, which logged its coldest temperatures in nearly four decades. It's going to get worse. Minnesota already cancelling monday's classes for the first time in 17 years. It's brutal, look at these bubbles in buffalo and massachusetts, shattering in the cold. The cold weather workers don't break so easily. But here in the emergency room, cold means danger. What are your biggest concerns here in this er room today. My largest concerns would be folks underprepared for the extreme temperatures, not liming their time outside, not dressing appropriately. Reporter: If you're worried your body temperature is too low and you may be suffering from hypothermia, look out for the umbles, stumbling, mumbling, fumbling or grumbling, all signs to go inside. And take a look behind me, this is lake michigan here in chicago, completely frozen over in the harbor, the wind starting to pick up. It's getting colder and colder. Just a taste of what's to come. That arctic blast, diane. All right, gio, that brings
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