Why Is "Wind Chill" So Dangerous?

Weather Talk

POSTED: Friday, January 24, 2014 - 1:54pm

UPDATED: Friday, January 24, 2014 - 2:15pm

Cold Winds Steal Heat From Our Bodies Putting Us At Risk From the Elements

A very cold Canadian Arctic air mass blew into the Borderland yesterday. The winds peak winds topped out at anywhere from 30 to near 60 mph as the powerful cold front pushed in from the northeast. My news producer’s thought it was an excellent idea to put myself and a camera woman out side  last night for the start of our 5, 6 and 10 P.M.. newscasts. When I was out in the blowing, icy cold air I thought maybe it was some kind of punishment,  they were some how blaming me for the 20º+ chill down!  Then I started thinking about wind chill. Wind chill is when the wind sweeps away our natural heat insulation by forcing cold air against us. We lose heat and out body temperature drops. In today’s “Weather Talk” I will talk about the factors that produce wind chill, the dangerous effects on our bodies and health and what we can do to better protect ourselves.

What exactly is “wind chill”? First let me talk about body temperature. The body keeps a constant temperature by converting food into heat (metabolism). To maintain a stable temperature, a balance is kept of the heat produced and absorbed to the amount of heat loss to the surroundings. There is a constant exchange of heat between the body and the environment, especially at the surface of the skin. All our bodies emit and absorb infrared energy. The body also loses and gains heat by conduction and convection which help transfer heat to and from through air molecules. When it is cold outside, slower moving cold air molecules bounce against our exposed, warmer skin and take some heat with them. Why is when the winds are calm the temperature actually feels warmer than the actual air temperature? This is called the sensible temperature. When there is no or hardly any wind, a thin layer of heated air molecules forms close to the skin, protecting it from the cooler molecules and from heat transfer. When the wind begins to blow, this insulating layer of warm molecules is swept away and our body heat is quickly removed from our skin by the continuous bombardment by the colder molecules. The faster the wind blows, the more heat loss, the colder we feel. The wind chill factor is how cold the wind makes us feel.

Here is the “New” Wind Chill Temperature Index that the National Weather Service implemented in November, 2001.
Chart: National Weather Service and NOAA;

Image: National Weather Service and NOAA

This rapid heat loss from our bodies and skin exposure to the cold can result in dangerous health problems.
First, high winds in below freezing temperatures can remove air from exposed skin so rapidly that the skin may actually discolor and freeze. The freezing of the skin is called frostbite. Frostbite usually happens on the body extremities first, like your hands or feet, because they are the greatest distance from the source of the body heat.

The amount of moisture in the air plays a big part in how cold we feel. A cold, damp day will feel colder than a cold “dry’ day because moisture is a better conductor of heat away from the body than “dry” air. If your exposed skin gets wet, your body heat removal speeds up and your sensible temperature drops. When you add the wind factor to a cold, damp day a person may lose heat faster than the body can produce it. The rapid loss of body heat lowers your body temperature and when it drops low enough it could bring on a condition known as hypothermia. Hypothermia is when the body temperature drops so rapidly that you start to lose mental abilities and then you can physically collapse and possibly die. The first sign of hypothermia is exhaustion. You may start to shiver or feel like you have to urinate. As time goes on a person starts to lose their power of judgment and reasoning. Extended exposure, especially at temperatures at or below freezing, produces a drunk-like stupor, collapse and death when the body temperature drops below 79ºF (26ºC). The crazy thing is most hypothermia happens when the temperatures are between 32ºF (0ºC) and 50ºF (10º)! Many times people do not realize that their cold, wet clothing in windy conditions greatly enhances their loss of body heat, even when the temperatures are above freezing. Quickly get the affected person out of the wind and the cold. If their clothing is wet, remove it gently and carefully. There could be frostbite or damaged skin that could be further injured from rough handling. Quickly get the affected person out of the wind and the cold. If their clothing is wet, remove it gently and carefully. There could be frostbite or damaged skin that could be further injured from rough handling.

If you find some one in this condition get the person inside and away from the cold and wind as fast as possible. If their clothing is wet, slowing and carefully take it off as their skin could be damaged by the frost bite.
Do not heat up a person with hypothermia or frostbite quickly!
You will cause thermal shock if you use anything hot. Dot not place a person in hot water a sauna or use a heating pad, do not serve them a hot beverage. You can use lukewarm water. Call 911 and take them to a healthcare facility.

Dressing warmly is the first prevention step you need to take against the cold. Wear layers, many thin layers trap more warm air close to your skin. Wear anything wool! Wool keeps you warm even if it gets wet, unlike other fabric material. Wool socks are a must, because they will make you feet feel warmer even if your shoes or boots get wet. Your body loses the most heat from your head and your hands and feet. Wear a hat and gloves or mittens!
You need to take shelter from the blowing wind and avoid wind chill! If you out in the wilderness find a large tree, even a snow drift, any barrier to hid behind, If you are in an urban area, sit behind a car tire, in a doorway any where out of the path of the wind!

Also,  remember when you are out in cold, skiing, hiking or even watching a game. Do not drink alcohol in an attempt to "feel" warm. Alcohol actually lowers your body temperature!

Now I think we have a better understanding how the wind can really steal heat from our bodies, what kind of health risks we are taking when we are out in the cold and how we can better dress and protect ourselves against winter’s harsh conditions and the cold. I think I am going to make sure my news producer’s, director’s and my boss read this “Weather Talk” so they know the risk and danger they are putting myself and my camera person in every time they plan on have me report live in outdoors on cold, wind evenings! No seriously I do love it, but even I have to stop and think about “whether” or not I and properly dressed for the "weather".

Chuck DeBroder, Chief Meteorologist
KTSM, NewsChannel 9, NBC, El Paso, TX
www.twitter.com/ Chuck DeBroder NC9 @wxchuckNC9

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