Two newly identified patterns in the stratospheric polar vortex can send cold air over North America to cause extreme cold snaps, but the parts of the country that suffer differ between them. Those ...

Harsh weather moved west as a polar vortex was expected to grip the Rockies and the northern Plains after winter storms pummeled the eastern U.S. over the weekend, killing at least 10 people.

These polar vortex stretches are happening more frequently as the world — and especially the Arctic — warms, a 2021 paper published in the journal Science, also co-authored by Cohen, demonstrated.

LOUISVILLE, Ky. — Harsh weather moved west on Monday as a polar vortex was expected to grip the Rockies and the northern Plains after winter storms pummeled the eastern U.S. over the weekend, killing ...