The Tennessee Valley was under a Wind Chill Advisory Wednesday morning, and at the coldest point, we dipped to -9 at 7AM. A Wind Chill Advisory is valid when wind chill values are expected to fall below 0. However, it takes extremely cold wind chill values for frostbite to develop within minutes, and luckily we're not experiencing those types of wind chills.

In order for frostbite to occur within 30 minutes to exposed skin, the wind chill must be -19 or colder. Within ten minutes, the wind chill must be -33 or colder,
and within 5 minutes -48 or colder.

The wind chill takes into account the temperature and the wind.

With wind chill values like what we've experience, it could take hours before frostbite sets in. Frost nip however is the precursor to frostbite. This is called a first-degree frostbite, and only affects the surface of the skin. No permanent damage happens, as the skin's only top layers are affected. Look for numbness to the skin. The skin is usually pale and sometimes has yellow patches.

According to the National Weather Service, the wind chill criteria is based on tests by adult volunteers. Children have not been tested. However, since children lose heat faster than adults, especially those with medical conditions, it's assumed the threshold should be lower for children, especially those with a circulation illness like diabetes.

Have a weather related story idea? Feel free to email Meteorologist Brittany Beggs.