An arctic blast will send temperatures across the United States plummeting as bitterly cold air that originated in Siberia will arrive from Canada by week’s end, bringing with it dangerously cold wind chills for millions of Americans.

Snow and winds are likely to trigger flight cancellations and cause headaches for people traveling to DC for Inauguration Day.

How the Polar Vortex Can Bring Arctic Blasts to the U.S. Vast weather patterns can carry blasts of frigid air far from the polar regions—here’s how it works