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What's A Polar Vortex? Five Things You Should Know About This Arctic Blast

National Weather Service
Expect another cold night tonight.

A blast of arctic cold hit North Texas Sunday night and Monday. And it’s sticking around a bit longer.

Here are five things you should know about this blast of arctic air:

1. How low did we go on Monday?

Pretty low. Way below freezing. Dallas-Fort Worth International Airport recorded a low of 15 degrees around 7 a.m. Monday. But that’s balmy compared to the wind chill – factor that in and it felt like 1 degree overnight.

Ouch.

As the day rolled along, we climbed into the low 30s.

It hasn’t been this cold in North Texas since February 2011, which was a very cold month.

But, you know, it could be worse. Parts of the upper Midwest have been stuck in temperatures of 30 degrees below zero. The town of Embarrass, Minn., reached 40 below zero – and that doesn’t include the windchill.

That’s not just embarrassing – that’s dangerous.

2. The cold weather wasn’t kind to the power supply.

ERCOT, the operator of the electric transmission grid for much of Texas, warned Monday morning of potential rolling blackouts.

The bitter cold caused electricity demand to surge. At the same time, the temperatures caused problems with two large generation units in north Central Texas. Some of the instruments used to control the units froze. ERCOT won’t say where these units are located.

On Monday morning, Texans consumed 55,486 megawatts – that was just about 2,000 megawatts away from capacity. ERCOT’s winter record was 57,265 megawatts in February 2011.

3. How is ERCOT trying to avoid a similar situation Tuesday?

ERCOT says that crews were working around the state to ensure that as much capacity is in place for the rest of Monday and Tuesday. They’re reminding generator and transmission owners to winterize their units, such as insulating them, to protect them from high winds.

And ERCOT is encouraging customers to conserve energy as much as possible Monday night and into Tuesday – try to keep your thermostat below 68 degrees.

4. There’s a new term floating around – polar vortex. What is it?

Move over cobblestone ice,the phrase that symbolized December’s ice storm in North Texas.

The polar vortex is basically a hurricane of really frigid air that moves counter-clockwise. It’s strongest during the winter. It usually stays way up around the North Pole. The cold air has been locked in up there and had time to get colder and colder. But a chunk of it escaped and headed south, invading most of the United States over the weekend and into this week.

NPR has more on the polar vortex.

5. How long will Ol’ Man Winter be sticking around in North Texas?

Expect one more bad night. Monday night, temperatures will be in the teens across North Texas -- perhaps as low as 12 degrees up north in Sherman.  DFW International Airport might be the hot spot at 18 degrees.

But it warms up Tuesday – temperatures should climb into the upper 40s.

We could hit 60 degrees Friday -- it'll be practically a heat wave. 

Eric Aasen is KERA’s managing editor. He helps lead the station's news department, including radio and digital reporters, producers and newscasters. He also oversees keranews.org, the station’s news website, and manages the station's digital news projects. He reports and writes stories for the website and contributes pieces to KERA radio. He's discussed breaking news live on various public radio programs, including The Takeaway, Here & Now and Texas Standard, as well as radio and TV programs in New Zealand and the United Kingdom.