snow-covered polar vortex rural scene with trees
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Two words people have learned to dread in the past few years is "polar vortex."  People may not know a lot about what that is, other than it usually means we may be in for some bitterly cold temperatures. 

The worst outbreak in my experience was December 23, 1983. I had just finished my graduate work and was beginning to look for weather-related jobs. So, I was living back at home on the farm. The farmhouse was uninsulated, and my bedroom was upstairs with no heat.

While I was used to sleeping with multiple blankets, I could tell that night was different. Under so many blankets I could hardly move, I was still cold. When I got up that morning, the temperature outside was -24 Fahrenheit, and, with the wind was howling at about 40 miles per hour, the wind chill was around -60.

This Arctic blast traveled south, and though its temperature moderated, it still killed most of Florida’s citrus trees.

What is the Polar Vortex and why does it feel the need to visit Illinois? In simplest terms, picture a large loop of winds that circle the poles. These strong winds act as a boundary, usually keeping the very cold air near the poles from moving south (or north if you are in the southern hemisphere). However, in certain situations, the vortex is weakened and broken into smaller vorticies. One or more of these pockets of very cold air are allowed to move away from the poles.

What causes a weakening of the vortex? One cause is a rapid warming of the atmosphere about 10 to 30 miles high.  Unfortunately, that very thing has been observed over the Arctic recently. Though this doesn’t occur often, it does occur every few years. When this rapid warming occurs, the chances of Arctic air reaching Illinois is enhanced.

Though we cannot predict with certainty we will get a cold blast in the next few weeks, all I can say is keep plenty of blankets on hand, just in case. 

duane friend

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MEET THE AUTHOR
Duane Friend is an energy and environmental stewardship educator with University of Illinois Extension, serving the organization in many roles since 1993. Duane provides information and educational programs to adult and youth audiences in the areas of soil quality, weather and climate, energy conservation, and disaster preparedness. These programs provide practical solutions for families, farms, and communities.  He assists families in creating a household emergency plan, farmers with the implementation of soil management and conservation practices, and local government officials and business owners with energy conservation techniques.

ABOUT THE BLOG
All About Weather is a blog that explores the environment, climate, and weather topics for Illinois. Get in-depth information about things your weather app doesn't cover from summer droughts to shifting weather patterns.