Recognize signs to avoid skin damage.

• Position: Frostbite

When the temperature dips below freezing, it is critical to protect your skin from cold-weather health risks. Frostbite occurs when the skin --and sometimes the tissue beneath it--freezes due to prolonged exposure to cold temperatures. Depending on how frozen the tissue and how long it has been in that state, frostbite can result in severe, sometimes permanent, damage.

"Frostbite usually affects the face, nose, ears, fingers, and toes. So, on bitterly cold days, it's not enough to just put on a winter coat," cautions Amy J. Derick, clinical instructor of dermatology at Northwestern University, Chicago, III. "To really protect your skin from dangerously low temperatures, keep an eye on the weather, dress appropriately for outdoor activities, and stay dry."

To prevent frostbite:

* Dress in loose, light, comfortable layers to help trap warm air. The first layer should be made of a synthetic material, which wicks moisture away from your body. The next layer should be insulating. Wool and fleece are good insulators and hold in more body heat than cotton. The top layer should be windproof and waterproof. A down parka and ski pants can help keep you dry and warm during outdoor activities.

* To protect your feet and toes, wear two pairs of socks. The first pair, next to your skin, should be made of moisture-wicking fabric. Place a pair of wool or wool-blend socks on top of those. Your boots also should provide adequate insulation. They should be waterproof and cover your ankles. Make sure that nothing feels tight, as tight clothing increases the risk of frostbite.

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