“And how far are you from shore?” he asked, and I tried to use the echo off the rock walls or trees to gauge my distance. Sometimes he’d say, “The wind is moving directly up-canyon, so paddle into it. If you feel it trailing to your left or right, you’ll know you’re off course.”

Our system improved steadily. We scouted Triplet Falls, one of the most challenging rapids on the river, and despite Rob telling me about two huge boulders I needed to avoid (known as The Birth Canal) and another nasty rock section called The Sieve, I decided to go for it. With Rob’s precise commands, we snaked right through the entire rapid.

At eighteen miles into the Gates of Lodore, the river widened and the skies opened overhead. Near a big buttress called Steamboat Rock, the Yampa River joined the Green, adding considerable flow and creating bigger, toilet-bowl-swirling currents that tried to tip me over. I had to fight hard to keep the nose of my boat going where I wanted it to. But after that, it was mostly easy water, and Rob added a few new commands. “Charge!” called for short, powerful strokes to gain quick speed and was needed to accelerate through small holes. “Stop!” required me to back-paddle with a quick burst of two to three strokes to cease forward progress downstream, an important skill for getting properly set up above a rapid. And “Stop paddling!” meant to let my paddle blade trail in the water and coast along, awaiting instructions.

Rob also started yelling out “Eddy line!” to alert me to upcoming eddies, and on easier flat water, we experimented with him yelling “Follow me!” and then transitioning back to me in the lead as we entered the next rapid. As Rob tucked in behind me, it felt like we were race cars jockeying for position. In this way, we were starting to perform our own fluid river dance, choreographed by Rob’s voice and our combined actions.

By midafternoon, we made the Jones Hole campsite, where we hiked up a creek to check out pictographs and petroglyphs left by the Fremont people a thousand years ago. Some designs appeared humanlike. Others were antlered animals and lizards, and the kids loved them. But in the intense July heat, our favorite was a section of Jones Hole Creek called Butt Dam Falls. We took turns standing in the cascading waterfall. Directly above our heads was a perfect butt-size depression in the narrow channel in which you could sit and temporarily block the water flow. Arjun couldn’t get enough. He’d sit above us, butt-blocking the stream, tempting his victims to stand below. He’d, of course, promise to hold back the flow, but as soon as we’d take the bait, he’d yell “Cowabunga!” and lift his cheeks, and the cold water would come pouring down over our heads.