According to the National Weather Service, a polar vortex will impact most of the country this weekend, here is what you need to know.

Americans were bracing Thursday for frigid temperatures that forecasters said could produce life-threatening conditions, with Donald Trump's inauguration expected to be the coldest in 40 years.

The polar vortex is expected to reach the Utah-Idaho border sometime in the late afternoon and evening Friday as it continues to move south. As it moves through parts of the state, it will produce small snow showers, bringing more snow to the region before drier conditions return.

A blast of Arctic air is set to cover much of the United States with temperatures below freezing starting on Friday and into next week, impacting millions of Americans in nearly all of the contiguous states.

However, a deep freeze, thanks to the polar vortex dipping down from Siberia, is about to bring even harsher arctic blast to nearly 300 million Americans starting this weekend. Maps show where and when the cold front will arrive.