At Christmastime, Jack Frost nipping at your nose sounds cute. When you are shoveling snow in January, you worry about meeting his ugly cousin, frostbite. While hypothermia, the lowering of core body temperature, is deadly, frostbite---freezing of the skin and underlying tissues--- can cause permanent tissue damage, as well as lead to amputation and disability. The Mayo Clinic reports there are three stages of frostbite. Frostnip, the first stage of frostbite, doesn't cause permanent skin damage