These are my touchstones in a landscape that is falling apart. The balance is tenuous and sweet. I keep finding ledges or boulders that I remember from long ago, little crux moves that get you from one impossible point to another. Superimposed on this place where everything is moving is the record of my own fleeting life, a shifting map where waypoints are memories, and rock is only a little less ephemeral than paper.

In my 40s, I traveled for a book project. I came back through the airport in Grand Junction, Colo., where Regan pulled to the curb in our dusty SUV. She had our two boys strapped in the back seat in a nest of juice boxes, books and toys. The rest of the vehicle was packed tight with camping gear. Exhausted from handling kids on her own, she spoke little, shifted into drive, headed west. I didn't have to ask where.

She took us to Utah, then 40 miles down a red-dirt road. Night fell. Our headlights probed sage and gullies as she put us in 4-low. The drifted desert fell into slickrock canyons. We camped on bare sandstone -- a tent and two bleary-eyed kids dragging blankets and sleeping bags. We zipped ourselves in under the stars.

In the morning, as my family slept, I slipped out before dawn. To the east, a violet band vibrated over the horizon around the black batwings of the La Sal Mountains; to the west, the last stars faded. I followed fingers of short, steep canyons, and soon sunrise turned the rock from fawn-colored to hot pink. The land became shells and shadows, shapes of sandstone worn by wind and water.

My book had taken me to Greenland, Chile and Tibet, farther from my home than I'd ever been. The maps I carried of these places told me little about how to travel, to survive; they told me nothing of what I would find there. I felt ungrounded, coming and going so quickly I could not possibly learn my place. When I stayed on an island in the Bering Sea between Alaska and Siberia, the Yup'ik Eskimos would not let me walk alone more than three miles from their village. They were wisely concerned about my ignorance of polar bears and tundra wolves.

Now, I could breathe again. There was no trail or rock cairn, only one foot in front of the other, fingers grazing boulders, taking in every shade and stroke of light. It was like coming back to your own house from a long journey, standing in the entry, suitcases set down, everything just the way you left it: a book on a table, a lamp in a corner, pillows on the couch. I could close my eyes and still see the way the sere horizons spread out from and around me.

Where sunlight filled the mouth of a low, wind-hewn shell of rock, I ducked inside. On the ceiling, I discovered a chiseled inscription, dated 1913, from a trapper who had worked these rivers: MY HOME.

A million or two years ago may have been too early for Canyonlands. You would not have seen this same canvas of erosion. A million or two in the future may be too late. Erosion will entirely sweep it away.

Kent Frost, the legendary author of My Canyonlands, spent his life here. Born in 1917, he explored it inside and out, a guide who had himself fallen in love. He knew it the way I imagine bighorn sheep do, remembering every key ledge and toehold in impossible terrain -- an entire landscape packed into his heart.

I met Frost down on the Colorado in the late-1990s. I was guiding a small group when I spotted him. Frost was in his late 70s then, button-up shirt, straight gray hair clipped around his face. He had come down on a Park Service raft and there were park rangers on his beach. I landed my group and jumped off to shake his hand.

I had to go fast. I was working under Park Service radar as a pirate outfitter, using a private permit to take paying guests down the river. A tanned, floppy-hatted 29 years old, I stood out. Everyone else in my group was over 60 and pale. I stuck with a quick, nervous, Hello, so honored to meet you Mr. Frost, I am a man after your own heart. Then I wrangled my group back onto the water before the rangers could follow up on their growing suspicions. When I waved back at the old explorer, he wasn't looking. His hands were stuffed in his pockets and he was peering up at the surrounding ledges and cliffs.

Frost became part of my own map, remembered much later for the feel of his skin loose on the bones of his hand, and for the clear sun, the texture and placement of the boulders, the robin's-egg strip of sky visible from the canyon in the place where we met.

In 2012, I heard he was in a nursing home in Blanding, Utah, rapidly losing his faculties. Some friends and I cooked up a plan to break him out and drive him somewhere with a sweeping view of Canyonlands. I didn't know Frost at all and was told that moving him would only discomfort him. But I imagined it would do him good to see the country as he remembered it. I would want the same some day, I thought, the last thing in my mind the shape of the earth that I love. But in May of 2013, before we could act, Frost died.

Our maps don't last. They are not supposed to. Wind polishes rock. Flash floods hollow out canyons. Two rivers carry away sediment in thick muddy boils.

I never marked my waypoints on any paper map -- where I met Frost for the first time, where I fell in love, where I said goodbye to my father and welcomed my sons into this labyrinth of a place. If someday I cannot remember where I've been, the heart of these rivers and canyons will pump on without me until, long after I am gone, they too wash away.