A polar vortex is engulfing the US. Here's what that really means, and why these events might be getting more common.

AP

• The polar vortex is sweeping parts of the US Midwest and East Coast this week, forcing nearly 220 million Americans to contend with below-freezing temperatures. 
• The polar vortex is an area of circulating cold air that ring the planet's North and South poles. Sometimes that vortex destabilizes, sending surges of Arctic air south.
• Windchill temperatures could hit minus 50 degrees Fahrenheit in North Dakota, South Dakota, and parts of Minnesota, far below average for this time of year.
• Officials warn that frostbite can strike within minutes at these frigid temperatures.
• If Arctic ice continues to melt, polar-vortex events could get more frequent.

For the first time since 2014, the polar vortex is descending on North America.

In parts of the Midwest and New England, about 25 million Americans are about to experience temperatures of  minus 20 degrees Fahrenheit. Some areas in Minnesota and the Dakotas are facing temperatures 50 degrees below average — that's life-threatening cold.

See the rest of the story at Business Insider

NOW WATCH: How long you can stay in extremely cold temperatures before getting frostbite

See Also:

• The polar vortex striking the US will cause temperatures to plummet up to 40 degrees colder than normal
• How long you can stay in extremely cold temperatures before getting frostbite
• Scientists just drilled the deepest hole ever in western Antarctica, going 2 kilometers down through the ice to study how it's melting

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from Business Insider https://read.bi/2SieluM