A polar vortex is a large blast of freezing cold air sent down from the North Pole. Somewhat rare, these tend to happen only once a decade, sometimes once every couple decades or so.
This polar vortex will likely be the worst we've seen in 20 years. Temperatures in the midwest are expected to drop down with wind chills of 50 degrees below zero.
It won't be that bad in North Andover. But we will see temperatures drop down Monday night and stay below freezing for most of the week, according to WHDH.
That will be a sharp drop from the highs in the 50s Monday to the teens on Tuesday and Wednesday.
Things will start to thaw by the end of the week.
Here are some tips, courtesy of the National Weather Service, to keep in mind during this Arctic cold.
1. Minimize outdoor activities, especially for the elderly and very young.
2. Dress in several layers of loose-fitting clothing rather than a single layer of heavy clothing.
3. Wear a hat, mittens and waterproof boots. Cover your mouth with a scarf to protect your lungs.
4. When using heating sources such as fireplaces, wood stoves and space heaters, be sure to ventilate them correctly.
5. Test smoke alarms and keep carbon monoxide detectors handy.
6. Bring pets out of the cold. Don't assume they can handle the cold. If you are not warm, they are not either.