Today (January 6th, 2014) schools in Central Ohio are closed due to the very cold conditions. The wind chill will be talked about frequently this week and beyond. The wind chill is the temperature it "feels like" outside. The windier it is, the faster the skin and the rest of the body cools. The wind chill dropping makes frostbite more likely. Frostbite is an injury due to frozen body parts. Exposed extremities including fingers, toes, ears, and the nose tip are the most likely to be injured by frostbite. Frostbite causes white, numb skin. See this link to the Healthy Children website for more information. Here is the National Weather Service's brochure on Wind Chill. It includes the updated Wind Chill Chart. This is how the temperature and wind speed are used to calcite wind chill. It is also possible to see how many minutes until frostbite will occur.
So dress warmly, dress in layers, keep extremities covered, and stay indoors as much as possible. Stay warm out there!