Excerpt from Between a Rock and a Hard Place by Aron Ralston, plus links to reviews, author biography & more

Colossal flood action has scooped out beach balls of rock from the sandstone walls and wedged logs thirty feet overhead. Slot canyons are the last place you want to be during a desert thunderstorm. The sky directly above the canyon might be clear, but a cloudburst in the watershed even ten or twenty miles away can maul and drown unwary canyoneers. In a flood, the rain falls faster than the ground can absorb it. In the eastern United States, it might take the ground days or weeks to reach saturation and for rivers to flood after many inches or even feet of rain. In the desert, the hard sunbaked earth acts like fired clay-tile shingles, and a flood can start from a fraction of an inch of rain that might come in five minutes from a single storm cloud. Chased off the impermeable hardscrabble, the downpour creates a surging deluge. Runoff gathers from converging drainages and quickly becomes a foot of water in a forty-foot-wide section of the canyon. That same amount of water becomes a catastrophic torrent in a confined space. Where the walls narrow to four feet, the flood turns into a ten-foot-high chaos of churning mud and debris that moves boulders, sculpts canyons, lodges drift material in constrictions, and kills anything that can't climb to safety.

In this meandering section of the narrow canyon, silt residue from the most recent flood coats the walls to a height of twelve feet above the beachlike floor, and decades of scour marks overlay the rosy and purplish striations of exposed rock. The undulating walls distort the flat lines of the strata and grab my attention in one spot where the opposing walls dive in front of each other at a double-hairpin meander. I stop to take a few photographs. I note that the time stamp is a minute slow compared to my watch: The digital camera's screen says it is 2:41 P.M., Saturday afternoon, April 26, 2003.

I bob my head to the music as I walk another twenty yards and come to a series of three chockstones and scramble over them. Then I see another five chockstones, all the size of large refrigerators, wedged at varying heights off the canyon floor like a boulder gauntlet. It's unusual to see so many chockstones lined up in such evenly spaced proximity. With two feet of clearance under the first suspended chockstone, I have to crawl under it on my belly -- the only time I've ever had to get this low in a canyon -- but there is no alternative. The next chockstone is wedged a little higher off the ground. I stand and brush myself off, then squat and duck to pass under. A crawl on all fours and two more squat-and-duck maneuvers, and I've passed the remaining chockstones. The defile is over sixty feet deep at this point, having dropped fifty feet below the sand domes in two hundred feet of linear distance.

I come to another drop-off. This one is maybe eleven or twelve feet high, a foot higher and of a different geometry than the overhang I descended ten minutes ago. Another refrigerator chockstone is wedged between the walls, ten feet downstream from and at the same height as the ledge. It gives the space below the drop-off the claustrophobic feel of a short tunnel. Instead of the walls widening after the drop-off, or opening into a bowl at the bottom of the canyon, here the slot narrows to a consistent three feet across at the lip of the drop-off and continues at that width for fifty feet down the canyon. Sometimes in narrow passages like this one, it's possible for me to stem my body across the slot, with my feet and back pushing out in opposite directions against the walls. Controlling this counterpressure by switching my hands and feet on the opposing walls, I can move up or down the shoulder-width crevice fairly easily as long as the friction contact stays solid between the walls and my hands, feet, and back. This technique is known as stemming or chimneying; you can imagine using it to climb up the inside of a chimney.

From Between A Rock and a Hard Place by Aron Ralston, pages 1-30.  Copyright © 2004 by Aron Ralston.  All rights reserved, no part of this excerpt maybe reproduced without specific permission from the publisher.