In 2021, a cold wave swept across the U.S., bringing freezing temperatures as far south as Texas. Millions of people lost power, and hundreds died.
Yale Climate Connections meteorologist Bob Henson says this cold wave was caused by disruptions to the polar vortex in the stratosphere, a few miles above Earth.
“The polar vortex is a loop of winds that encircles the North Pole. This loop of winds can stretch. It can break into two pieces across the course of a winter,” he says. “So the polar vortex stretched pretty dramatically, and that allowed cold air to be funneled from the Arctic down into the United States well into Texas.”
