Structure is not a template. It’s not a cookie cutter. It’s something that arises organically from the material once you have it. In “The Encircled River” I go to Alaska, and make that trip, and soak up that world. And when you’re up there, the most impressive thing is the cycles of that world. There aren’t any people up there in that Salmon River valley, not even Eskimos. Cycles of one year, five years, a thousand years: all these different cycles spinning around. The cycles of the wildlife, the different species and how they come and go. This sort of gets into your head and keeps going on and on.
But once I started writing, I had to tell a story. It’s the story of a journey. Within that journey certain things happened, such as an encounter with a big grizzly. That grizzly encounter was a pretty exciting thing, and it happened near the beginning of the trip. That was somewhat inconvenient structurally, because it’s such a climactic event. But you can’t move that bear, because this is a piece of nonfiction writing.
But what if you started telling the piece of writing further down the river, I wondered. That way, when you get to the end of the trip, you’re really only halfway through the story. What you do then is switch to the past tense, creating a flashback, and you back up and start your trip over again. By the time you get to that bear, that bear is at the perfect place for a climax. That’s what’s exciting about nonfiction writing. In this case it’s a simple flashback, but it also echoes all these cycles of the present and the past.