With my eyes half-closed in horror, we began our descent down the narrow 21-foot waterfall. "Hold on," our guide yelled over the deafening noise. Screams of fear mingled with shouts of excitement.

We quickly plunged down, down, down into the churning, frothy white water. At the bottom of the cascade, we were sucked under the raging river. Our raft ricocheted back out of the water and flipped over, landing on my head, pushing me farther into the cold, wet darkness.

Whose idea was this, I wondered. My 62-year-old mother, 22-year-old brother, and I were visiting relatives in New Zealand for Christmas a few years ago. After experiencing several stimulating but benign cultural offerings, my adventurous cousins were eager for more daring activity and suggested white-water rafting along the Kaituna River outside Rotorua. As a family, we had rafted only once on a fairly tame section of the Arkansas River in Colorado, but nothing compared to the 21-foot Tutea Falls.

"The guides wouldn't take us unless it was safe" was the general opinion. Although not entirely satisfied with my brother's and cousins' assurances, I allowed myself, a 29-year-old, to be persuaded. How bad could it be?

As we started out in our rafts, the scenery was beautiful. We passed through a narrow gorge with sheer rock walls bursting with ferns and other native plants. After I successfully navigated two small waterfalls, my confidence was high.

Even Tutea didn't look that ominous from the top. But then next thing I knew, I was thrashing beneath the roiling water, and all I could think was: "Oh, my God, I am going to drown. I can't breathe. I'm not going to make it. Oh, my head hurts."

Suddenly, I remembered the guide's instructions: "Grasp hands around knees, make yourself into a ball, and you'll float up." I did it and shot up through the water. I made it - only to find myself beneath the overturned raft.

I gulped down deep breaths of air, inhaled, and forced myself back down. I felt my way outside of the boat and re-emerged above the surface, clear of the raft.

Terrified, desperate, and unaware of my surroundings, I tried to climb onto the overturned raft, only to have the guide direct me to the other side so he could flip the raft over.

Meanwhile, my aunt was nearly washed away by the powerful current. My mother, who normally refuses to put her head below water when swimming, had forgotten the safety technique and felt as though she was drowning. She also had a large welt on her hand from being hit by a paddle.

Back at headquarters, my mother was terrified, my brother was exhilarated, and I was in pain. Whiplash is not limited to auto accidents; I got mine from being whacked in the head by the airborne raft.

The rafting company then told us that heavy rainfall had swollen the river, and five of seven raft trips had capsized that day. A little too much information way too late.

We also discovered that the 21-foot drop was the world's highest commercially rafted waterfall.

Enough was enough, I decided. But my brother persuaded us to book a dolphin-watching trip out of Opotiki the next morning. Great - more water!