Exposure to the elements is one of the greatest threats to survival in Antarctica. Sunburn, which is much more likely to affect you in such a reflective environment, is not only uncomfortable but dangerous. It can block your body's ability to sweat and thereby cool itself, it can lead to fever and retarded muscular activity if severe, and, because of the ozone hole, can ultimately increase your chances of getting skin cancer.

Frostbite, the freezing of tissues, can strike any exposed skin in minutes. (Note that beards offer little or no protection to your face.) The first sign is a blanching of the affected area, followed by a tingling or stinging sensation and then numbness. If the affected area stops hurting, you know you're in serious trouble. On Elephant Island, Perce Blackborow had to have all the toes on his left foot removed after they had become severely frostbitten. Never forget, too, that flesh can freeze instantly to frozen metal.

The gravest danger of exposure is hypothermia, which is a lowering of your core body temperature. It comes on surreptitiously; people have died of hypothermia without ever even complaining of the cold. Initial symptoms include exhaustion, loss of mental acuity and judgment, and a reluctance to do anything. When your core temperature drops below 78°F, you die.