The northern United States is currently facing a severe cold snap caused by a southward shift of the polar vortex, a large area of low pressure and frigid air typically surrounding the Earth's poles. Temperatures have plummeted as low as -20°F (-29°C) in some areas, prompting the National Weather Service (NWS) to issue widespread warnings about dangerous wind chills. These conditions pose significant risks of frostbite and hypothermia, urging residents to take immediate precautions.