From the moment we got on the river, it was different from any experience I had ever had, like paddling through a real-world Jurassic Park. As we raced along, the slurp and gulp of the enormous hydraulic features sounded alive, like riding the back of a gargantuan, slithering snake disappearing into an endless jungle. The shoreline teemed with the lionlike roars of howler monkeys, the piercing calls of macaws, and the lengthy drum-croak of giant toads.

The first couple of days were devoid of big rapids, but the immense volume of water coursing downstream created challenging river features even Rob hadn’t experienced before. Giant phantom boils would surge up randomly and explode a couple of feet higher than the river’s surface. The way Rocky described them, the massive energy of the river moving downward wasn’t consistent. The water flowing far beneath the surface would get slowed down by boulders or sped up by drop-offs, and it would create different currents that rose up, sometimes colliding with other currents and erupting at the surface like lava from a volcano. It was disconcerting to be paddling downriver and suddenly realize the bow of my boat was pointing uphill in a boiling upheaval. Even more frightening were the enormous, unpredictable whirlpools or, as Rocky called them, vortexes.

Like the boils, the vortexes materialized out of nowhere and moved across the water, but instead of pushing up, these sucked you down. Rob could spot them for me, calling out, “Whirlpool on the left! Hard right! Hard right!” But they arose and then vanished, reappearing some arbitrary distance away. It was impossible for Rob to call out all the appearing, shifting, and reappearing features that gave the river a crazy, chaotic energy, like angry fingers shoving, lifting, spinning, and pulling my boat under.

To increase my stress level, the new radios we were trying out provided no improvement. They were muffled and inconsistent, and often I had to guess what Rob was yelling at me to do. I flipped a bunch of times on the upper section, all the while getting hypertense about what lay ahead. Sometimes, the pitching and bucking would get so overwhelming, I’d ask Chris or Rob to link up in a flotilla. I’d grab their boats and desperately latch on. It was strange that even though I couldn’t see, squeezing my eyelids tight somehow helped fight the sense of dizziness.

One afternoon, I got flipped upside down by a boil that rose up right in front of my boat. I tried to hit my roll, but the boil bumped me into a massive whirlpool that spun me around and sucked at my helmet. I worked to get my paddle to the surface, but the vortex yanked the paddle blade downward.