How is the polar vortex affecting temperatures in Dallas, Texas?

Dallas is experiencing extreme cold with temperatures at approximately 19 degrees Fahrenheit and a wind chill making it feel like just 2 degrees. The conditions are so severe that it's actually warmer in Reykjavik, Iceland and Anchorage, Alaska than in Dallas right now. This polar vortex is affecting a wide region from Minneapolis to Texas, forcing millions of Americans to navigate slick roads or stay indoors to avoid the dangerous conditions.