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11 things to know about the sub-zero cold

Here are some tips and information to make it through a cold snap safely.

Editor's note: The video above originally aired in January 2019.

1. This isn't unusual for Minnesota

In fact, it's been worse! The DNR's Climate Journal shows the lowest wind chill ever recorded in the Twin Cities was -67º on January 22, 1936. It sounded even worse at the time, since forecasters were using an older calculation model, which put the wind chill at -87º!

2. How do forecasters determine wind chill?

Here's how the National Weather Service explains it:

"The windchill temperature is how cold people and animals feel when outside. Windchill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature."

The weather service adopted a new mathematical formula starting in 2001, based on updated technology to make it more accurate:

Windchill (ºF) = 35.74 + 0.6215T - 35.75(V^0.16) + 0.4275T(V^0.16)

Where: T = Air Temperature (F)
V = Wind Speed (mph)
^ = raised to a power (exponential)

The National Weather Service also developed a chart to determine how the air temperature and wind speed combines for the wind chill, and how quickly frostbite can develop as a result.

3. What is frostbite?

"Basically the tissue freezes, and when the tissue freezes, the blood supply to the involved tissue is cut off," said Dr. David Dries at Regions Hospital.

Frostbite most often affects extremities when they're exposed to the cold air, like your fingers and toes, or even your nose. Mayo Clinic says the first symptoms often include loss of feeling and cold, discolored skin.

4. How is frostbite treated?

Use warm water, but not hot, to rewarm the skin.

"The important thing to do initially is to rewarm the tissue. You can put the tissue in warm water, typically it can be as warm as 100 degrees," said Dr. Dries. "The tissue may be numb. It may be very difficult to move your fingers or toes initially. That should improve rapidly with rewarming in warm water. If that doesn't happen then you need to visit an emergency department."

Doctors say you may also notice swelling or blistering in more severe cases.

RELATED: How to protect yourself from frostbite

5. What is hypothermia?

Hypothermia is a condition where your body temperature falls below 95º. Mayo Clinic says symptoms include shivering, slurred speech, lack of coordination, drowsiness, confusion, and loss of consciousness.

6. How is hypothermia treated?

It starts with warming up your core. Focusing on your limbs first could send all that cold blood to your heart, which can be dangerous. Be sure to get into dry clothing, and wrap up in a blanket, including your head. Also, you can try warm--again, not hot-- food or drinks; and definitely not alcohol, which can lower your body temperature.

7. Dress for sub-zero temps

Layers, layers, layers. As the National Weather Service points out, the air that's trapped between the layers can help provide extra insulation. Don't forget a hat; and mittens are more effective at keeping warm than gloves.

8. You don't need to warm up your car for very long

Your engine doesn't necessarily need that warm up time. Most automakers only recommend about 30 seconds. Driving your vehicle actually warms the engine faster, which allows the heater to warm up more quickly.

Of course, your car's battery should be in good condition to allow your engine to start up at all.

9. Have a winter survival kit in your vehicle

The Minnesota Department of Public Safety has an online brochure filled with advice for winter driving, including recommended items for a winter survival kit. Some of the noteworthy items include a flashlight, extra phone charger, spare batteries, a few snacks, jumper cables, a shovel, and sand or kitty litter to pour down to give your tires traction.

10. Run your water to prevent frozen pipes

Plumbers recommend running your sink occasionally to prevent frozen pipes, more than just a trickle.

"When you have a pipe that’s beginning to freeze, having new water flow through it will melt that ice that’s building up," said T.J. Knatcal with TJK Plumbing in Maple Grove, who also recommends keeping exposed pipes warm. "It’s a good idea to open those areas up that have piping in them."

11. Keep your thermostat steady

Many heating experts suggest keeping your thermostat set to a steady temperature when it's super cold, instead of lowering the temp when you're away; that way the furnace doesn't have to work extra hard to make up the difference. Also, be sure the filters are changed in your heating system, and be sure to clear any blockages around your heating vents to keep the air moving.

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