Our plan was to hit the trail head at 6:00 in the morning, hike eight miles in to an alpine lake in the Bitterroot Selway Wilderness, fish the late morning and early afternoon, and hike out that afternoon, carrying plastic bags full of monster cutthroat trout with flesh as pink as salmon.

Six miles up, at seven thousand feet, it began to rain. We kept hiking. Frigid air screamed down the draw. We hid under a tree, but it was raining sideways, so we got soaked through our shorts and T-shirts.

My teeth started chattering, so we ate some snacks we'd brought along, thinking some calories would help. I reached down to unsnap my canteen from my belt, but I couldn't manage the simple task; my hands wouldn't work.

"I can't feel them," I told my friend with a laugh.

Fortunately, my friend, who was also beginning to shiver, realized that we were in trouble. He suggested we head home immediately. I stumbled behind him numbly. There would be no fish today.

I was in hypothermia, a deadly condition in which ...