When Chris went down with a broken leg halfway through the portage, I started doing the numbers—25 miles against a strong current back to the put-in, then God knows how long a hike to the nearest home. No way. The takeout was 52 miles downstream, through a dozen named rapids we'd never seen. That would take four days at the rate we were moving. I stared up at the sheer rock walls that towered 1,000 feet above the river. Forget it.

"The loneliest river in the lower 48 states." That's how one guidebook describes the East Fork of the Owyhee River in southwestern Idaho. Despite the river's unparalleled beauty, few people are willing to run it due to its remote location in the high sagebrush desert. Not to mention the difficult quarter-mile portage around Owyhee Falls. Even without a critically injured team member, the portage takes several hours. We'd been here close to six.

I glanced at my nine tripmates, strung out along the steep slope of tufted grass and scree that swept hundreds of feet down to the falls. Lynn, 69, nursed a bad ankle and a persistent cough. Bob and Martha, both in their mid-60s, slumped beside their packs. Burt and I were both 59, me with a bad shoulder. If we pushed too hard, we risked another injury.

One number could have saved us: 911. Burt had a satellite phone, but didn't know if he could establish a signal down in a thousand-foot-deep canyon. He spotted a nub of rock that stuck 50 feet out from the slope, giving him a marginally better window. "I'll climb up there and start calling," he said. "Let's hope we get lucky."

None of us talked about what would happen if we didn't get lucky. If we had to paddle Chris out four days in the bottom of a canoe, we were looking at an amputee, or, if complications set in, possibly a dead man.

I stared at the ashen ribbon of water surging through the rocks below. "This is no river for old men," I said.

Burt scratched his gray beard. "Don't count us out yet, John."

Wild places have a way of testing one's limits. When you travel into remote wilderness as part of a group, you not only have to trust your own experience and ability, but those of your partners as well. Paddling tandem canoes through whitewater only accentuates that challenge. Our group of adventurers was used to it.

We call ourselves the Tarheel Canoe Club—an informal group of 20-odd people, mostly from North Carolina, united by a love of whitewater canoe tripping. In various combinations, we have tackled more than a dozen marquee wilderness rivers, including the Lower Canyons of the Rio Grande, the Lower Salmon, and the Mountain River in Canada's Northwest Territories. Most of us are over 50, half are in their 60s. Chris and his wife, Monica, both in their mid-30s, are the babies of the group. We pay no dues and avoid formal meetings. Instead, we receive invitations in the mail from our leader, Burt Kornegay, owner of Slickrock Expeditions in Cullowhee, N.C.

This year's letter outlined a long, challenging trip—seven days and 77 miles through a spectacular canyon, running half-a-dozen Class III-IV rapids and portaging 500 feet up and down the side of the gorge. The water temperature in May would be in the 40s, the air temperature in the canyon could range from the 30s to the 90s. "Pack accordingly," Burt wrote.

Some months later, on a cool, cloudy morning, we rumbled in a four-wheel-drive shuttle vehicle down an eroded track to the put-in at Garat Crossing. The East Fork of the Owyhee looked harmless, a shallow stream running through a sage-brush meadow. We unloaded our tandem canoes, donned our paddling gear, and sat down for a quick lunch.

Just as the shuttle driver disappeared over the horizon, the clouds unleashed a fusillade of hail. I crouched in the sage, wishing I'd spent the extra $20 for an insulated helmet liner. In keeping with Burt's edict, I'd purchased more than $500 worth of gear, including Hydroskin baselayers and matching "semi-dry" paddling jacket and pants. They were not enough to keep away the chill.

Even the rocks proved hazardous. Leaning backward in the sage, I brushed my hand across a piece of razor-sharp basalt and split open two of my fingers. I dug into the medical kit and eventually staunched the flow of blood, but for the rest of the trip, I would have difficulty gripping my paddle.

When the hail finally abated, we paired up, launched our canoes, and rode the swift current into the canyon. Dark columns of basalt, formed eons ago from rapidly cooling lava, rose straight up from the riverbed. Tim, my bowman, spotted a herd of bighorn sheep on a narrow ledge.

"Not bad for our first afternoon," Tim said.

Then, the headwinds began. What started out as intermittent puffs rippling the surface turned into withering blasts that stopped the canoes dead in the water.

"Paddle, woman!" Bob called to Martha.

"I'm paddling as hard as I can!" Martha snapped.

It was the first time in a decade of canoeing I'd heard her use that tone of voice.

Everyone's patience was wearing thin, and by the end of a second wind-ripped day, we were thoroughly beat. We dragged our canoes onto a gravel bar, sagged against the "couch" (a pair of overturned canoes) and downed shots of whiskey. Lynn coughed uncontrollably. I rubbed my aching shoulder. As darkness fell, I retired to my tent and inflated my coveted air mattress, hoping to get a good night's sleep before facing the portage around Owyhee Falls. But sleep wouldn't come.

Muscle aches are a normal part of a hard day on the water and, with the help of a couple of Ibuprofen, they usually disappear overnight. But my shoulder pain wouldn't quit. The condition I suffered from, swimmer's shoulder, felt like a meat hook lodged in my trapezius muscle. Every time I took a forward stroke or rolled onto my side, the hook dug in. I lay there in the dark, wondering if I could go on another five days.

The question was moot, of course. The only way out was forward, so the next morning I swallowed more Advil and pressed on. We reached the portage just before noon. We could neither hear nor see the waterfall that necessitated our diversion, but Burt's map assured us this was the place.A faint path led from the river's edge straight up a steep slope of tufted grass and loose rock.

I strapped on a 70-pound food pack and started up the trail. The incline was so steep that I could touch the trail ahead with an outstretched hand. Just when I thought I couldn't go another yard, the trail leveled out and ran along the base of a sheer cliff. I caught a glimpse of Owyhee Falls far below. The trail started down.

In my early teens, at a canoe camp in Canada, I portaged many rocky trails and learned the importance of looking before planting my feet. As I labored down the side of the gorge, I recited a mantra: "See the rock, step on the rock." I dumped my pack at the river and headed back for another load. Lynn passed me coming down, his face gone white.

"Bad news," he said. "Chris slipped on a loose rock. His leg is broken."

When I reached him, Chris lay on his back at the highest point of the portage. His foot was turned at a right angle, the tibia and fibula protruding beneath the skin. Monica cradled his 220-pound frame from behind, while Perry, a family physician, removed his boot and ran a finger over his arch.

"Can you feel that?" Perry asked.

Chris nodded yes.