Frostbite isn't usually a major worry here in Washington, D.C., but with wind chills below zero forecast for half of the Lower 48 by Tuesday morning, millions of people from the Plains to the East Coast will have to start thinking like Arctic explorers while waiting for a school bus or heading to work.
Noses, fingers, toes and ears face the biggest risk. Those body parts have less blood flowing through them and a lot less mass than the body's core. They're also more likely to be exposed to the elements. Obviously, bundling up those tender parts is key.