Extreme exposure of your feet to cold over for a prolonged period can lead to a serious condition called frostbite. If the skin changes color from blue to white, or you feel numbness in your toes or feet, you may have frostbite. People with a history of frostbite often get it again in the same place. New battery-powered heated ski boots and exothermic packs are effective in preventing frostbite.
If you suspect that you have frostbite, seek emergency medical care as soon as possible. Ensure that your feet are dry and warm, but do not expose the flesh to extremely warm or hot temperatures. A gradual and steady warming procedure should be followed.