As Told to Devon O'Neil
WHEN I LEFT MY HOUSE in Moab last December, I was just going out for an easy two-hour run with my dog, Taz. I'd finished an adventure race a couple weeks before and was transitioning to the winter season: snowshoe racing and winter triathlon.

About an hour in, I was scrambling out of a remote canyon to connect one trail to another. It was cold, and there had been a frost. The ground was ice. My foot slipped out from under me, and I started sliding down a smooth rock face on my back, picking up speed like on a waterslide. The next thing I knew, I went over a 20-foot ledge and smashed into the canyon floor. I didn't know the extent of the damage at first, had no idea I'd broken my pelvis in half. My initial reaction was just: I have to get out of this canyon.

I started dragging myself with my arms, because the rest of my body was useless. That was at about noon. I stopped at five, when I reached a puddle of snowmelt. I drank but tried not to drink so much that I would pee, because wet clothes would mean a better chance of dying from exposure. It was dark by then and temperatures had dropped into the twenties. I knew I had to keep my core warm, so I started doing stomach crunches. I also tapped my feet and wiggled my hands in my crotch to keep the circulation going. I put on a shower cap that I had in my waist pack. (We carry them during adventure races because they trap the heat from your head.) I also had two packs of energy gel. Otherwise, I was just wearing lightweight pants, a polypropylene shirt and thin fleece, and a fleece hat. I knew if I fell asleep I would probably get colder, so I stayed awake all 52 hours, which I'm used to from adventure races. I did crunches the entire time.

By the next morning the endorphins had worn off, and my pelvis had gotten so heavy from internal bleeding that it was dead weight. Any attempt to move brought the worst pain I'd ever felt. All I could do was keep yelling for help. Taz didn't really understand what was wrong at first. But on that third day, I was desperate. I remember telling him that I was hurt and asking him to go get help. He ran the four miles out to my truck, which, luckily, the police had found. When Taz saw the rescuers there, he acted really agitated, jumping away and barking whenever they tried to approach. He made eye contact with one of them and took off toward me, and they realized that they needed to follow him. Just a couple of minutes after Taz got back to me, a rescuer arrived on an ATV.

A doctor later told me that most people with an injury like mine die within ten hours. After my surgery, they said I was going to be in a wheelchair for between six and 12 months. But six months after the accident, I'd already done three adventure races.

Expert Analysis: First off, Taz rules! The shower cap was genius. You can lose 30 percent of your body heat through your head. The decision to try to stay dry was also a good one. Any activity that produces heat is helpful to stave off hypothermia, and staying awake would keep one more aware of numb or exposed places that needed special attention.

Staying hydrated and minimizing additional bleeding from excessive movement were key. Every time you rub fractured bone ends together, you may not only lacerate vessels but also disrupt blood clots that have formed.

As for the injury itself, if it was an unstable pelvic fracture, I can tell you that these can be lethal within hours. —Dr. Luanne Freer, former president of the Wilderness Medical Society and founder of Everest Base Camp Medical Clinic