SITUATED at the edge of the Colorado Plateau, a vast rock tabletop that encompasses parts of southern Utah, northern Arizona, southwestern Colorado and northwestern New Mexico, Zion National Park is a geological wonderland hundreds of millions of years in the making. The rock here was tortured by nature, having at various times been uplifted, tilted and eroded. As a result, the land looks like a giant staircase, with each step several thousand feet higher than the next. And it is riddled with deep, narrow canyons -- ideal territory for the sport of canyoneering.
A more extreme offshoot of simple canyon hiking, canyoneering is a multiskill sport that combines climbing, rappelling and swimming to descend steep slot canyons -- the narrow gorges in mesas, sometimes a yard wide and several hundred feet deep and often filled with frigid runoff.
Part of the time, you're simply walking down a streambed in water up to your ankles or knees, but you're eventually faced with obstacles like waterfalls that must be climbed down or rappelled and rapids and pools that must be swum. All the while, you're surrounded by high rock walls, often too steep to climb if you suddenly need to get out. The sport can be dangerous, and it is not unusual occasionally to hear about a canyoneer who died in a fall, drowned in a whirlpool or was swept away in a flash flood.
The modern version of the sport did not originate in the Southwest, where many of its practitioners now go to hone their skills, but in France and Spain in the 1970's. It came to this country about 15 years ago and has progressed from being a largely esoteric pursuit practiced by a handful of extremists to a small but thriving sport catered to by outdoor gear manufacturers and several instructional schools. Jonathan Zambella, owner of Zion Adventure in Springdale, Utah, which teaches the sport's basics to hundreds of vacationers a year, estimates that there are only about 50 hard-core canyoneers in the Zion area and 1,000 in the Southwest, mostly in southern Utah, the sport's main American playground.
According to Mr. Zambella, any relatively fit person can learn the basics of canyoneering and become qualified to go on self-guided adventures (with at least one other person) in some of the easier-rated slot canyons in Zion and elsewhere. In fact, there may not be a better way to explore Zion. (Paid guiding is actually not allowed in the park; Mr. Zambella teaches in canyons just outside its boundaries.)
He offers one-day and three-day basic canyoneering courses ($149 and $495), which introduce students to all the necessary gear and cover rappelling, route-finding and preparing for unexpected challenges like flash floods. At the end of the course, he will tell you if you are ready to tackle the canyons without a guide -- a judgment call that some critics suggest can be a little too lenient, given the dangers of the sport -- and will rent the necessary equipment. As for the critics, Mr. Zambella responds that everybody is a beginner at something.
Recently, I signed up for a special two-day course. I learned how to assemble rappelling gear and don the polyrubber dry suit and climbing harness. I learned how to properly tie the knots to set up rappels, how to select anchors (should I tie my rope to a live tree, boulder, dead log?) and how to unclip from the rope when I reach the swirling pool at the bottom. The other students and I made about a dozen rappels off waterfalls, a few of them as high as 200 feet. At the end of the program, Mr. Zambella set us up to do our first canyon, unguided: a Class 3b III canyon called the Subway.
(Under the American Canyoneering Association canyon rating system for grading routes, a ''1'' signifies an easy canyon hike and a ''4'' is for experts only. The next component -- the letters ''a'' to ''c'' -- represent the water volume or current, with ''a'' meaning the stream is usually dry with some waist-deep wading, and ''c'' signifying strong current and multiple waterfalls. Roman numerals from I to VI indicate how long the route will take under normal conditions, from a short trip to a trek of two or more days.)
The Subway was a 7.6-mile trip that included several miles of intense canyoneering. In the bowels of the canyon, the walls on either side practically touch overhead, creating a tubular cave that Mr. Zambella said was going to be a challenge for me and my friends, all of us neophytes, but was ''very doable.''
Carrying about 20 pounds of gear and water in our backpacks, we hiked from the parking area atop a grassy mesa with patches of snow down over slick red bowl-shaped rock then down a plummeting red-dirt trail through a ponderosa forest. I could see why the 19th-century Mormons, whose progeny still inhabit the southwest corner of Utah, called the area Zion, the Hebrew word for ''heavenly place close to God.'' All around me, soaring sandstone walls and narrow slot canyons formed an otherworldly landscape and a divine playground.
Finally, we reached the bottom of the slot canyon, which varied from being as wide as a two-lane road to being so narrow we had to sidestep through it. It was also rushing with water. After about a quarter mile of hiking down the center of the stream and a short rappel down a boulder that was in our path, we heard it, roaring like a demon -- then we saw it. Our first waterfall. About 20 feet, it wasn't particularly tall, but we could tell that descending into it would require some tricky maneuvering, and below it was a roiling whirlpool. There was nowhere to go but down.
The scary part, as I had learned in my basics course, was leaning back for the first time as you drop over the edge of the waterfall. You are never quite sure if the rappelling device, called a piranha because it is shaped somewhat like the fish, is going to hold your weight. Soon I was dangling from the rope, my feet pressed against the wall, my face pummeled by ice-cold sheets of water. I suddenly slipped, and my shoulder slammed into the wall at full force, but I soon regained control.
It became easier after that. When I reached the bottom, I disengaged the rope and swam out of the swirling plunge pool to the nearest sandbar. It was my turn to sit back and watch my pals descend. With all of us at the bottom, we shared a few high-fives. We had conquered our first waterfall, but we didn't celebrate too much. We still had four waterfalls and a steep hike up the side of the canyon to go. Floating like beach balls in our dry suits, we swam farther downstream until we heard that familiar rushing sound. We took out our ropes and prepared to descend.
While the adrenaline keeps you focused and intense, it's hard not to think occasionally about the danger you face on such an adventure. One often-repeated story looms large in the Zion canyoneering world.
In July 1993, a Mormon youth group from the Salt Lake City area embarked on a three-day expedition in the Kolob Canyons. Things went wrong almost immediately. After rappelling 150 feet, the inexperienced canyoneers discovered that the water was running much higher than they had expected -- knee-high instead of ankle -- making the current significantly faster. Prevented from climbing out by the slick canyon walls, they headed downstream to the first waterfall, where one of their leaders drowned in the swirling plunge pool at the bottom. A few hundred yards farther downstream, a second leader drowned. Unable to continue, the five teenagers and the surviving leader huddled on a sandbar and fought hypothermia for four days before they were rescued. ''They were out of their league,'' Mr. Zambella said.
One way to reduce the chance of injury or death is to stay out of the canyons during rainstorms and be especially wary in July, August and early September when monsoon rains soak the desert Southwest and flash floods are common. Other tips can be found at the American Canyoneering Association Web site (www.canyoneering.net). The organization, based in Cedar City, Utah, promotes safety and the exchange of information, and addresses issues involving canyoneering with land management agencies.
Of course, the point isn't to be afraid of the sport. Once you are competent, you can enjoy the thrill of exploring beautiful places that cannot be reached any other way. In the upper canyons, you will see prickly pear cactus, yucca, mesquite and sagebrush as well as juniper and pinyon. A little lower, giant ponderosa and wildflowers prevail. At the bottom is a wet paradise with cottonwoods, box elders, velvet ash, and ferns. Springwater seeps out of the canyon walls, allowing hanging gardens of moss, algae, maidenhair fern and golden columbine to grow.
There aren't many guidebooks on the best places to go, so any trip to Zion must begin with a cup of morning coffee at the Mean Bean, a cramped, one-room coffeehouse in Springdale, less than a mile from the park's south entrance. Fit, athletic locals -- some with dreadlocks, others with no-nonsense buzz cuts -- chat, tell jokes and share stories from the backcountry.
The owner, Joe Hovorka, is a T-shirt- and shorts-wearing chatterer with a crew cut and a propensity to spray his left-of-center political views like a machine-gun fire as he shouts over the roar of the espresso machine. He has some concerns about this new trend. As he sees it, instructors like Mr. Zambella are sending inexperienced canyoneers into places they do not belong. And he says it is only a matter of time before more people are lost, hurt or killed, putting local rescue personnel unnecessarily at risk. ''You can tell the ones that are a tragedy waiting to happen just by looking at them,'' Mr. Hovorka said. ''They're usually outfitted to the nines and drive the biggest S.U.V.'s.''
Nevertheless, he doesn't mind seeing well-outfitted yuppies, those readers of glossy outdoors magazines and wearers of $150 sunglasses, pull into town. Not only does he like most of them once he gets to know them, but they like to fuel up with coffee before heading into Zion's spectacular slot canyons. ''Somebody's got to sell it to them,'' he said, ''and it might as well be me.''