Polar vortex: What is it and how does it happen? January 30, 2019 at 02:35PMhttps://https://bbc.in/2G1YryU The deep freeze gripping much of the US has been blamed on a polar vortex. Here's what that means.

The deep freeze gripping much of the US has been blamed on a polar vortex. Here's what that means.

from BBC News - World https://bbc.in/2Sex5LW