I had passed the man, a veteran Iditarod musher, seated in the snow. He smiled and waved at me like a casual spectator. His manner struck me as odd, but I had no time to wonder why. My lead dogs leaped over a fallen log, and the others swiftly followed. My sled smacked the thick trunk, went airborne, and I steered it through the air.

Later I learned the cause for the musher’s strange expression. As his dogs jumped that same fallen tree, the unlucky racer had caught a leg under it. Something had to give against the pressure exerted by his 12-dog team. He let go as his leg splintered in a compound fracture. Another racer paused long enough to prop the injured musher in the snowbank, where I saw him, while local kids fetched help. Shock was apparently setting in by the time I passed by.

Leaving the lakes behind, we climbed a few hills then entered a broad lane through thick trees. The trail here was well-packed, a sign of heavy traffic. Not far ahead, I knew, a sharp turn was coming, one I’d been warned not to miss. From that point onward, Klondike racers followed some 70 miles of the Iditarod Trail, a historic gold-rush route to the Interior mines.

I was still looking for that turn when Casey showed signs of lagging. No surprise there. We’d been on the trail more than an hour, and that was Casey’s usual limit for leading. I swapped her with Raven, but my little black-haired princess wasn’t in the mood to run out front. She kept darting left and right, tripping Rainy, her coleader, and the swing dogs running directly behind. After several pauses to untwist lines wrapped around careless paws, I played a hunch and moved Harley up front.

Harley and Rainy made an odd, but effective pair. Rainy was one of our kennel’s smaller dogs, weighing 35 to 40 pounds at most, with brown hair and squirrellike movements. Harley cut a hulking figure, twice her size and splotched black, white, and brown. When he ran, Harley’s ears flopped up and down, keeping time with his lumbering stride.