In the latest instalment of the Indiana Jones franchise, the titular hero gets swept over a massive waterfall along with his companions. Amazingly, they survive the plunge unscathed. Dr. Jones doesn’t even lose his trademark hat in the river.

This summer while exploring an all but unknown river in the Hudson Bay watershed, I found out first-hand what it is like to be swept over a waterfall. Unlike in the Hollywood versions, it didn’t go quite as smoothly for me: I was a bit banged up, my canoe was even more so, but worst of all, I lost my Indiana Jones hat. Over the years, I had worn it on countless expeditions and even a few archaeological digs. It had survived all that the elements could hurl at it, through wind and rain, sleet and hail, until that unforeseen waterfall swallowed it up.

But to explain how I found myself plunging over a waterfall in the first place: I had set off to explore a river that no explorer, surveyor or canoeist had been down before. There was no way of knowing exactly what awaited me. My only guide was a set of dated topographical maps, the result of aerial photographs taken in the 1950s, which are too indistinct to detect waterfalls. Google Earth’s low-resolution satellite images, all that is available for this remote part of Canada, are no better. While these maps indicated plenty of rapids on the river, there were no known waterfalls.

It took nearly a week of bushwhacking and dragging my canoe up creeks to reach the river’s isolated headwaters. Once there, I could finally begin my descent of the waterway. The first day passed relatively uneventfully. The second day I encountered many small rapids. Being something of the impatient sort, I ran all of them. This was imprudent. In the midst of a series of rapids, I could suddenly hear an ominous roar downriver. The banks were high granite rocks and the rapids too swift for me to back paddle to safety. I was headed straight for the roar of water.

The next thing I knew the river had disappeared in front of me: it was a vertical drop. A WATERFALL! In a flash, I plunged over another rapid, then for a heart-stopping second, my canoe hovered right on the brink of the fall as the bow edged into the open air. In the next instant, I felt myself fling forward, catching a glimpse of my canoe flipping upside down in the drop as I toppled out and hit the water. I was sucked down beneath the fall, thinking to myself: “great, I’ve survived the drop...but shouldn’t I have reached the surface by now?” Then after what seemed like an eternity my head finally broke free of the river and I breathed in a living-giving gulp of air.

Bobbing in my lifejacket, the swift current was carrying me downriver. Out of my left eye I saw my overturned canoe, smashed out of shape in an eddy to the side of the waterfall. But I had no time to worry about it. My first priority was to make it to shore, then race ahead to recover my backpack and other gear, which were being swept downriver. Soaking wet and out of breath from the time I spent underwater, this was a challenge. With considerable luck, I eventually managed to recover all of my gear, minus my cherished hat, fishing rod and a pair of moccasins that were sitting in the front of the canoe when I plunged over. Fishing my overturned canoe out of the eddy was easy enough: repairing it was another matter. The oak gunwales were shattered, the hull crushed out of shape, the front seat broken and one side of the vessel punctured. There was little I could do about the gunwales or seat, but duct tape served admirably to patch the hole, and some hammering more or less put the hull back in shape. It wasn’t pretty to look at, but it appeared serviceable enough. Within two hours of my death-defying plunge, I was paddling downriver again.

While thrilled at discovering a waterfall (a fair accomplishment for any explorer), and even more thrilled that I had survived my plunge over it (a fair accomplishment for me, if not Indiana Jones), nothing could entirely dispel my dejection at the loss of my old hat. On the other hand, with it gone I wore my helmet for the remainder of the expedition, which proved providential, as it turned out that there were more undiscovered waterfalls waiting for me. But that is a story for another day.

Adam Shoalts has led an expedition supported by The Royal Canadian Geographical Society and is a Canadian Geographic contributor.