https://apnews.com/59002405452e61d702a9839f6eb99e6f > It’s as if the world has been turned upside-down, or at least its weather. You can blame the increasingly familiar polar vortex, which has brought a taste of the Arctic to places where winter often requires no more than a jacket. > Around the North Pole, winter’s ultra-cold air is usually kept bottled up 15 to 30 miles high. That's the polar vortex, which spins like a whirling top at the top of the planet. But occasionally something slams against the top, sending the cold air escaping from its Arctic home and heading south. It’s been happening more often, and scientists are still not completely sure why, but they suggest it's a mix of natural random weather and human-caused climate change.