ONE MORNING IN February 2006, my father skied into a tree. It was a dead one—limbless, barkless, grayish, like the light, and perhaps partly hidden behind a bigger, healthier tree, which he had just swerved to avoid. He hit it flush, face first, and the impact sent him sprawling down a steep open face, trailing gear and blood.

At that moment I was standing out of sight, in a glade down and across the slope, waiting for him to come bobbing happily through the firs. We were among a group of 12 guests that day at a cat-skiing outfit that operated in the Kootenay backcountry, outside Nelson, British Columbia. Our guide, as is customary, had urged us all to pair up while skiing through the trees, in case someone got lost, buried, or hurt. For years, my father and I had been a little lax on this score; fiendish about powder snow, we'd each hurtle through the woods and only on reaching the bottom of the run wonder, sheepishly, where the other might be. But this time I waited; I'd wandered away from the group, as a fiend will, and had had to cut back across the fall line to find the guide's tracks. I wanted to be sure that my father made the turn.

He didn't quite. It's possible that in reacting to my tracks he'd failed to see the dead tree. I can't say. I didn't see it happen. He came to rest about halfway down the face. Blinded but still conscious, he began to moan for help. After a few moments I heard these moans and climbed back up and across the slope toward him. The tail gunner, a kind of deputy guide who skis down last (and carries a radio), reached him just as I did. My father was sitting up, in deep powder. He had not been wearing a helmet. At the first sight of him—his face bloodied and mangled beyond recognition, his eyes suddenly plum-size and swollen shut, nose and mouth gushing, his remarks incoherent in a subtle, haphazard way that seemed especially ominous—I had a foreboding that he'd be dead within hours.

Three days later—after a difficult evacuation by sled and helicopter, a series of ambulance trips to bigger hospitals in bigger towns (Nelson, Trail, Spokane, New York), many dark hours, and then one piece after another of encouraging news—I was able to pinpoint when this feeling had left me, when I felt that he might be OK. It was in the hospital in Nelson, four hours into the ordeal. The nurse tending my father in the emergency room told him, in that loud talk-to-old-people voice that nurses sometimes use (my father was only 60 and otherwise in excellent shape), that she was going to cut off his ski clothes.

"Oh, no, you don't," he said, rather clearly for a man who'd fractured his skull and nearly every bone in his face. They thought he was kidding, but he wasn't. The man loves his gear.