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Arctic air sends temperatures plummeting across much of US

Eric Miller / Reuters

A woman walks her dog along Lake Harriet in Minneapolis, January 23, 2013. The Upper Midwest remains locked in a deep freeze, with bitter sub-zero temperatures and wind chills stretching into a fourth day across several states due to waves of frigid Arctic air.  Read the full story.

Millions of Americans are in the grips of a bitter arctic blast, with no relief in sight at least through the weekend and into Monday. The freezing temperatures and high winds are causing damage to buildings and are being blamed for several deaths. NBC's Craig Melvin reports.

Jim Michaud / Journal Inquirer via AP

Ice and snow changes our environment, as winter engulfs our world.