WATCH: The ‘polar vortex’ explained
by Cassady Sharp
Originally posted to Mother Nature Network Dangerous subzero temperatures are sweeping the United States in what meteorologists are calling a "polar vortex." In the midwest, wind chills are dropping temperatures to as much as 60 below zero. Watch below as two experts, Rutgers University's Jennifer Francis and Weather Underground's Jeff Masters, explain climate change, jet streams and the polar vortex.