Some reports sound like there’s a monster coming to kill us all.
“Scientists warn of possible polar vortex,” the headline on a major news site proclaimed on Dec. 20. Recently, the polar vortex term has become popular for its scary undertone. “It sounds like it could be some sort of alien death-ray…” said the National Oceanic and Atmospheric Administration’s scijinks.gov website.
What does it all mean? In essence, current weather outlooks suggest that we may get a few strong winter storms. There is nothing sensationally new in that. The circumpolar vortex, covered in every atmospheric science book, was first described in the 1850s, and explained in detail by Carl-Gustaf Rossby in 1939.
A cap of cold air turns over the Arctic. Where it meets warmer air, high-altitude winds get very fast. That boundary is called the jet stream. When the cold air expands, the jet stream bounces southward, and frigid air reaches the U.S. Southeast, along with a frontal system that can bring frozen precipitation. Bingo, the vortex has struck.
It shouldn’t make experienced Georgians emigrate to Costa Rica. Just think back to 1985. On Jan. 19, Gainesville had a low of 33 and a high of 50 degrees. The next night, “The Vortex” came, bringing a low of 8 degrees. The following night, it dropped to minus 8 Fahrenheit, turning all my house plumbing into solid ice. The afternoon barely reached 12 degrees. Daytime temperatures went above 32 a couple of days later, but it wasn’t until Jan. 31 that the nightly freeze-ups stopped.
Christmas of 1983 was worse, with temperatures dropping below zero, and freezing rain making North Georgia roads impassable. At the time, such outbreaks were called “Siberian Express.” Frigid air from Northern Russia was overrunning the Arctic, reaching North America.
The steering force in all of this was, and is, the jet stream. It works like a train track high up in the atmosphere, guiding the winter storms. When it swings southward, news stations like to mention the newly fashionable term.
Frozen conditions are certainly coming. But it’s not the vortex itself that will harm us. Car crashes, not freezing to death, are the major cause of fatalities in winter storms. The easiest way to guard against the main effects of the vortex is to keep tires in good condition, allow more travel time, and drive defensively.
Rudi Kiefer, Ph.D., is a professor at Brenau University, teaching physical and health sciences on Brenau’s Georgia campuses and in China. His column appears Sundays.