Ian Roth: As winter drags on and temperatures drop way down, your risk of cold-related injury like frostbite can go way up.

Sanj Kakar, M.D., Orthopedic Surgery, Mayo Clinic: Literally think of it as freezing of the tissues.

Ian Roth: Dr. Sanj Kakar, a Mayo Clinic Orthopedic hand and wrist surgeon, says frostbite is more common than many people think.

Dr. Kakar: We tend to see frostbite, for example, when the temperature is 5 degrees Fahrenheit with minimal windchill.

Ian Roth: If the windchill drops below negative 15 degrees Fahrenheit, not unheard of in the northern half of the U.S., frostbite can set in within half an hour. The most vulnerable areas of frostbite are your nose, ears, fingers and toes.

Dr. Kakar: Initially [with] the milder forms, you can get some pain and some numbness of the tips, but the skin can change its color. It can be red. It can be white. Or it can be blue. And you can get these blisters on your hands. And it can be a very serious injury.

Ian Roth: The worst cases, the tissue can die, and you may need surgery to remove it.

So who's most at risk?

Dr. Kakar: [Those most at risk are] certain patients with diabetes, patients who have previous history of frostbite are prone to it, the elderly or your very young children, and also, for example, if you're dehydrated.

Ian Roth: For the Mayo Clinic News Network, I'm Ian Roth.