Winter is the great undiscovered secret of the Western wilderness, as mountains, deserts, prairies and canyons retreat to an eerie, lonesome solitude. Spectacular stretches of terrain that draw great hordes in spring, summer and fall empty out completely this time of year, leaving a peculiar hibernal beauty.

The emptiness is not without reason, of course: Blizzards, sub-sub-zero temperatures and 12-foot snowdrifts may stay the staunchest of outdoor enthusiasts. But even though winter in the American Outback can be a daunting proposition, it has never kept me from journeying into the wildest West.

There was the night ski jaunt on Lizard Head Pass in southwestern Colorado, chinook winds whipping up glittery powder, stars blazing, coyote packs howling to each other across the snowy meadows. Another February week of camping and hiking in the Snake Range of Nevada brought warm days and chilly nights as we trudged the snowdrifts on 12,298-foot Baker Peak, sleeping next to the icy cataract of Lehman Creek. And a freeze-dried three-day weekend in the canyons of southern Utah saw nights so cold the cottonwood branches creaked and groaned, and animal tracks everywhere: owls, hawks, coyotes, rabbits, deer and, on an obscure ledge above the canyon floor, the prints of a lone lion. I've made dozens of these winter hegiras, each marvelous and gruelling in its own unique way.

And now I am bound for the southeastern Utah canyons again, with my friend Doug, a grizzly bear expert. It has been a dry winter so far, with little or no snow across the Four Corners area, where Colorado, Utah, New Mexico and Arizona meet. This means easy hiking in Grand Gulch, where we are headed, but crisp temperatures and scant drinking water. Things tend to even out, in the back country.

Grand Gulch is a Bureau of Land Management primitive area, roadless and protected because of its numerous Anasazi Indian sites and the grandeur of its deep sandstone gorges. A wonderful place. I have hiked Grand many times, but I still haven't explored all of it: Including its many side canyons, the Grand Gulch system is well over 100 miles in length.

On this particular trip, Doug and I plan to hike down Bullet, one of Grand's largest tributary canyons; we will follow the main gorge north till we run out of energy and enthusiasm, and then we will follow another side canyon, Sheikh, Todie or Kane, back out to the mesa top. We reckon it will take three or four days, depending, again, on energy and enthusiasm.

The drive from southwestern Colorado takes us through Cortez, past Sleeping Ute Mountain, along the San Juan River, past Montezuma Creek and Bluff, and, finally, up onto the massive escarpment of Cedar Mesa. By the time we get to the rim of Bullet, our jumping-off point, it is too late to start hiking.

We pitch our tents, build a fire of juniper and pinyon deadwood, and cook a dinner of steak, potatoes, carrots and onions wrapped in tinfoil (soy sauce the key ingredient). The sky ignites with a billion stars. The temperature plummets. An owl hoots nearby.

It must be late, 10 or 11 ... but no, it is just 7:30: These short wintry days really hit home out-of-doors. We turn in anyway.

The next morning we break camp and head down the canyon. We have two main goals on this trip, besides simple wilderness hiking: to take in as many Anasazi sites as possible -- particularly their petroglyphs and pictographs, the enigmatic art the ancient canyon-dwellers scratched and painted on the rocks and cliffs -- and to look for the bear.

A couple of months ago, while hiking the main gorge of Grand Gulch, I found the tracks of a massive black bear: a big surprise, as no bears have ever been reported in Grand Gulch. The bruin had evidently migrated down from the neighboring Abajo Mountains in search of nuts, berries and insects; it has been dry in the high country this year, and the bears' natural foods are in short supply. Doug says the bear has probably returned to the mountains by now to hibernate, but we still want to look.

The trek down Bullet is a beauty. We drop over a low place in the rimrock and descend the shallow gulch that is the upper canyon for a half hour or so. Then Bullet becomes a real canyon, dropping off into a series of steep, slick rock chutes and frozen pools. The cliffs rear up on both sides, glorious swooping planes of 250-million-year-old Cedar Mesa sandstone, 300-foot water stains on the blond rock. Tiny crooked trees cling to the cracks, and on one isolated ledge we spy an Anasazi storehouse of mud-plastered riprap.

The chutes give way to a canyon floor choked with brush and tumbled alluvium, with impassive dropoffs here and there. We traverse past on series of broad ledges below the north wall of the canyon, and then drop down into a lush subterranean oasis, with ponds, reeds and trees. A few more twists and turns, and we come out in the broad grassy meadow that will be our campsite for the night.

Canyon walls turn the already-short days even shorter, darker -- morning to evening in the blink of an eye. We make camp quickly, and head down-canyon to look at some Anasazi ruins and rock inscriptions a mile or two away. Best of all is the tiny cubicle of a structure nicknamed Jailhouse Ruin because of its window barred with wooden wands, still intact; above it, on the cliff face, three painted circles keep watch. They resemble moon, sun, owl's face: an animistic Native American Holy Trinity.

We walk back to camp in the chilly dusk, build a campfire and cook up a bunch of prefab chili with wild rice. Food you would scorn at home goes over like Brillat-Savarin in the wilds. It is a brilliant night, frosty and crystal-clear. A big shooting star rolls across the sky above the rimrock and explodes into darkness down toward Monument Valley, across the San Juan on the Navajo Indian Reservation.

Doug is a good companion for a backpacking trip. He looks a bit like a bear, with his stocky, powerful build and sloping shoulders, and like the Ursus horribilis he studies he is a tireless traveler. He never hurries, but moves at a ruminating pace, taking plenty of time to look for Anasazi rock art with his binoculars, check out human and animal tracks, study the convolutions and rugosities of the landscape.

Best of all, he is a good conversationalist, with a superb fund of stories: of his days as a Special Forces medic with the Montagnards in Vietnam, of travels in Alaska, Baja California and Manhattan, of adventures with bears, coyotes, killer whales, film producers and literary agents... . A near-perfect back-country compadre.

If he has a fault, it is a certain propensity for disorganization: He managed to break his ancient frame pack flying up from Tucson to meet me in Colorado, and he is using a pack I borrowed for him. He also forgot to bring along enough food, leaving us with barely sufficient supplies. We have dined well the first two nights, but from here on in it is going to be hungry going.

The hike down Bullet to the main gorge of Grand is lovely. We pause to fill our canteens at the spring below Jailhouse Ruin, and keep going, into the maze of tawny tone and shadow. Side canyons and side-side canyons, box gulches and alcoves coil away on all sides. Above are hanging gardens, cut off from the rest of the world by hundreds of feet of vertical rock; and higher, along the rim, gigantic sandstone pagodas, anvils, mushrooms, their tops as inviolate as the dark side of the moon. It is a mysterious, lost world, endlessly enthralling.

It is noticeably warmer at the bottom of Grand. We have descended almost a thousand vertical feet from the rim, and winter has ebbed. There are leaves and colors, living colors, jade, saffron, rust, and the thin silver sounds of trickling water: a taste of reborn autumn, of almost-summer.

We hike northeast, through thick brush, scrub oak and tamarisk. The afternoon shadows are lengthening when we reach the mouth of the side canyon where we will camp tonight: a canyon that is the site of a famous pictograph called the Green Mask. We hike up till we find the mask, and make camp nearby.

The Green Mask is a disquieting thing, an enigmatic jade visage with cold slot eyes and long roan hair. Surrounded by a host of other images -- humanoids, deities, beasts, Paul Klee-like geometries -- its presence rules the entire cliff face. Below the pictographs is a small ruined village, half-buried in fallen rubble.

Doug and I piece together what seems like a likely history. According to archaeologists, the Anasazis temporarily abandoned Grand Gulch around 100 A.D., driven out by drought; they took refuge in the mountains, and returned around 1050, when conditions were better. We figure the Anasazis returned to this particular village after their exile in the mountains and found it wrecked by rockfall. Before going further into Grand Gulch to build a new village, they covered the cliff above with their most potent symbols and images: The People of the Green Mask Have Come Home. Lending credence to our theory is the circle inscribed on one of the fallen boulders, obviously carved after the village was destroyed. Anyway, it makes a nice story.

The sunset is exquisite. Thin clouds have fumed up in the west, enough of them to catch the last sunlight and turn into masses of coral, bay, cadmium, madder. The rimrock catches the reflected glow, a neon-bright crest above the darkening depths of the gorge.

We are lower on food than I had thought: Dinner is dried-mix soup, a smidgen of chili, a couple of carrots, leaving nothing but some instant cereal and a little more dried soup.

The next morning, I decide to hike out, leaving Doug in the canyon an extra day. I will pick him up tomorrow. I shoulder my pack and prepare to hike on up the canyon; it looks like a jumbled mess, a jackstrawed obstacle course of alluvial rocks, timber and debris, but there must be a way out, somewhere. I hope.

Doug heads down the canyon, turning to wave once, then moving on. I watch him disappear around a corner of cliff, and then I start on my way. Immediately I run into trouble. I work my way along a nasty ledge to a pile of room-sized boulders that blocks the canyon bottom. With much huffing and sweating, I manage to climb up into a cramped space between the rocks, pushing my backpack before me. Then the only way up is through a tiny slot. I have to take off my parka and sweater to fit, and even then I get stuck for several awful seconds.

As I strain and wriggle, I notice the boulder above me is supported by a tangle of sticks and logs at one end, nothing more: From where I am, it looks like a mastodon toe-dancing on the tip of a knitting needle. Terror makes escape artists of us all: I am through the slot in about one point two seconds. Then I realize my pack is still on the wrong side of the passageway.

I reach my foot and pull it up. Then I have to take everything out of it, tent, bag, the works, to fit it through the hole. By the time I repack my gear, it is nearly 11; I have been "traveling" for an hour and a half, and I am about .008 miles above our campsite of the night before. At this rate, I will make it back to the van just in time for New Year's Eve.

Luckily, the rest of the route out is not that bad: There is some scrambling, bushwhacking and stonewhacking, but I move right along. The upper canyon is a wild place: There are deer tracks everywhere, with skeins of coyote prints threaded through here and there.

After a couple of hours, I find myself face-to-face with the last rimrock. I haven't seen any Anasazi signs since I left our campsite -- the upper canyon is too rocky for the corn, beans and squash agriculture that was the linchpin of Anasazi survival -- but now I find a little jewel of a ruin, under the canyon rim. Its inhabitants must have farmed the top of Cedar Mesa. One of the rooms has a beautiful ceiling, peeled beams and fine wands held together with dozens of loops of yucca-fiber cord: the inimitably graceful architecture of drought, faith, skill.

Topping out is like going from one world into another. Suddenly I can see forever, to the Red House Cliffs, the blue dome of Navajo Mountain, the Bears Ears, the Abajos. I take a long look, and then I start walking. It's still a hefty slog to the rim of Bullet, where we left the van. My pack seems to weigh a ton, and I am starving.

I mega-lunch on Navajo taco, salad, chocolate malt and coffee in Mexican Hat, and then I drive on up to Bluff and get a room at the Recapture Lodge. The mattress feels great, after three nights on a thin foam pad over cold, hard sand. For a moment I feel almost guilty, thinking of Doug, foodless in the depths of the canyon, but I quickly shrug the feeling off. I dine on cheeseburger, pie and coffee, and fall asleep watching an old 1930s gangster movie on television ... A just reward, for a winter adventurer.

I pick up Doug around noon the next day, along the road that runs north across Cear Mesa. He has hiked all the way up to Todie Canyon and out that way, bushwhacking and scrambling. He found several more beautiful petroglyphs and pictographs, and a perfectly-intact Anasazi storehouse on a remote ledge, its door still sealed. But he saw no bear tracks: Evidently the bear has returned to the Abajos to hibernate.

The mesa smolders all around us, incandescent sand, sagebrush, timber. More lost canyons wind away on both sides as we drive south, toward Mexican Hat. A golden eagle circles to the west, hunting.

Winter in the back country is addictive. We haven't even made it halfway to the cafe before Doug starts talking about a February trek down the Sierra San Pedro Martir of Baja California, and I find myself agreeing enthusiastically: There are paintings of mountain lions eight feet long on the cliffs down there, the gods of extinct Indian tribes and narrow gorges no one has ever walked, blocked by chockstones the size of houses and high, nameless waterfalls.

Winter treks in the West should be considered only by experienced campers and hikers who know the lay of the land and what gear to pack, as well as how to keep an eye on the long-term weather forecast. Several good books are available for boning up on winter skills; I recommend Harry Robert's "Keeping Warm and Dry" and Glen Randall's "Cold Comfort: Keeping Warm in the Outdoors." For more information on the Grand Gulch Primitive Area, contact the Bureau of Land Management, P.O. Box 7, Monticello, Utah 84535, 801-587-2141; the bureau warns that anyone considering winter hiking be aware that although Grand Gulch is a desert area, elevations are high and snow and ice accumulation can be heavy.

Rob Schultheis reports from Afghanistan and works on various film projects in his spare time.