I liked this analogy:

It’s like an ice skater spinning rapidly with her arms tucked in, he said. But when the polar vortex weakens, the arms start flailing out, the skater slips and “all the cold air then gets released away from the center of the polar vortex,” Cohen said.

The current cold outbreak is consistent with Arctic change and the polar vortex, Cohen said. “What we found is when the polar vortex stretches like a rubber band, severe extreme winter weather is much more likely in the United States. That’s where it tends to be focused and in January we have an extreme case of that stretching of the polar vortex.”