SIOUX CITY, Iowa (KCAU) — High temperatures are expected to remain below 0° later this week with wind chills expected to be -30° to -45° as parts of Siouxland have low temperatures of around -15° plus sustained winds possible of up to 30 mph and gusts to 50 mph. With cold temperatures and lots of wind on the way, it is important to stay safe when outside and know what to do to protect yourself from getting frostbite.

A “wind chill” refers to what an air temperature feels like to human skin from the combination of the air temperature and the winds blown onto exposed skin. In Siouxland, a Wind Chill Watch is issued usually at least 48 to 72 hours in advance where there is the possibility of seeing Wind Chills of -30° or colder. A Wind Chill Advisory is usually issued up to 36 hours in advance where wind chills of -20° to -29° are expected, whereas a Wind Chill Warning is issued up to 48 hours in advance where wind chills of -30° or colder are expected.

The reason why we get wind chill and how it matters is that when we have a cold temperature combined with the wind, we lose body heat through convection. The stronger the wind is, the faster we lose the body heat, but the weaker the wind is, the longer it takes to lose the body heat. We have a layer of warmth that helps us stay warm longer when we don’t have the wind. However with the wind, it gets sucked away a lot faster. This means that the warm layer breaks up when it is windy and speeds up the loss of the body heat.

National Weather Service’s Wind Chill Chart with frostbite times.

However, the colder it feels outside, the less windy it needs to be outside for us to lose the body heat, so it makes it feel that much colder, even though the wind speed is not as strong.

To stay protected from the cold, staying home is of course the best bet. However, if you have to be out, make sure you bundle up as much as you can with several layers of clothing, as any skin that is not protected can lead to those parts of your body getting frostbite. If you can wear at least a shirt, sweatshirt, and a very heavy jacket. Wearing a couple jackets would not be a bad idea either. For your face and head, make sure you wear a hat, scarf, and even a face mask. Make sure you also have boots that fit and are nice and tight, as boots that are too big could have cold air and snow get inside and make your feet very cold as well.

Frostbite can occur if wind chills are below 0°, where it could occur in a 30 to 60 minutes with wind chills between 0° and -15°. The colder it gets, the less long it takes to get frost bit, where wind chills of -15° to -30° could occur in 10 to 30 minutes. If wind chills are between -30° and -45°, this could occur in 5 to 10 minutes. If wind chills are -45° or colder, this could mean any part of your body could get frostbite in less than 5 minutes, or almost instantly in some cases.