The cold remains a mystery, more prone to fell men than women, more lethal to the thin and well muscled than to those with avoirdupois, and least forgiving to the arrogant and the unaware.
As you step around to orient map to forest, you hear a metallic pop. You look down. The loose bail has disappeared from your binding. You lift your foot and your ski falls from your boot.
You twist on your flashlight, and its cold-weakened batteries throw a yellowish circle in the snow. It's right around here somewhere, you think, as you sift the snow through gloved fingers. Focused so intently on finding the bail, you hardly notice the frigid air pressing against your tired body and sweat-soaked clothes.
The exertion that warmed you on the way uphill now works against you: Your exercise-dilated capillaries carry the excess heat of your core to your skin, and your wet clothing dispels it rapidly into the night. The lack of insulating fat over your muscles allows the cold to creep that much closer to your warm blood.
Your temperature begins to plummet. Within 17 minutes it reaches the normal 98.6. Then it slips below.
At 97 degrees, hunched over in your slow search, the muscles along your neck and shoulders tighten in what's known as pre-shivering muscle tone. Sensors have signaled the temperature control center in your hypothalamus, which in turn has ordered the constriction of the entire web of surface capillaries. Your hands and feet begin to ache with cold. Ignoring the pain, you dig carefully through the snow; another ten minutes pass. Without the bail you know you're in deep trouble.
Finally, nearly 45 minutes later, you find the bail. You even manage to pop it back into its socket and clamp your boot into the binding. But the clammy chill that started around your skin has now wrapped deep into your body's core.
At 95, you've entered the zone of mild hypothermia. You're now trembling violently as your body attains its maximum shivering response, an involuntary condition in which your muscles contract rapidly to generate additional body heat.
It was a mistake, you realize, to come out on a night this cold. You should turn back. Fishing into the front pocket of your shell parka, you fumble out the map. You consulted it to get here; it should be able to guide you back to the warm car. It doesn't occur to you in your increasingly clouded and panicky mental state that you could simply follow your tracks down the way you came.