Drought is a rude reminder that in any given year the interior West is but a storm or two from that hydrological tipping point where farming, ranching and the presence of cities become not merely ill-advised but — impossible.

The region is being reminded of this now in a big way: Five consecutive years of drought, six in some areas, are throwing a scare into urban water managers, driving farmers and ranchers off the land and threatening power shortages this summer as anemic river flows curtail hydro-electricity generation.

But there are some to whom the drought presents opportunity. On a warm day in late May, a small group gathered at a trailhead southeast of Escalante, Utah, to take advantage of that rare chance. Joining guide Travis Corkrum of Salt Lake City and freelance photographer Eli Butler of Flagstaff, Ariz., were six backpackers from four states who had signed up for an outing sponsored by the nonprofit Glen Canyon Institute.

Shouldering packs, they trudged across sand and slickrock, past blooming beavertail cactus and sage, to the edge of the plateau. At the lip of 900-foot-deep Escalante Canyon, they clambered down a vertical rock face and then squeezed through a crack in the rock barely wide enough for an adult. Gathering again at the bottom of the cliff, the group descended a steep slope and dropped into the inner canyon, setting up camp beneath an overhanging wall of Navajo sandstone.

The campsite was about a quarter-mile from the confluence of Coyote Gulch and Escalante Canyon, and more than 80 miles downstream from that confluence stands a dam, the 10-million-ton plug of gracefully arched concrete wedged into Glen Canyon. Not long ago, the enormous reservoir behind that dam backed up right to the campsite in Coyote Gulch. But things have changed since the drought began.

Lake Powell, which began filling in 1963, is at its lowest point in more than 30 years, 117 feet below maximum pool and at only 42 percent of capacity. Its boat-launch ramps have been extended hundreds of feet and Hite Marina has been closed altogether because there is no longer any water there.

The drought also has begun resurrecting the canyon system drowned more than three decades ago by Glen Canyon Dam, revealing to a new generation of Westerners the environmental cost of their water and power. And by doing that, the drought has reinvigorated a quixotic campaign to mothball the last of America's high dams, and to drain forever the lake it created.

"The drought is showing us why we don't need Glen Canyon Dam," said Chris Peterson, executive director of the Glen Canyon Institute, which was established in 1995 with the goal of decommissioning the dam and draining the reservoir.

Environmentalists for years have made their case against the dam in the language of scientists and engineers, debating evaporative losses and sedimentation rates with the U.S. Bureau of Reclamation. But the drought has given them an opportunity to change the tenor of that debate now that people can see some of the canyon for themselves. The trip in late May was the second such outing; several more are planned this year.

The goal of the outings is simple: to win converts to the anti-dam cause by giving visitors a first-hand look at the scenery lost beneath the lake and letting the landscape work its magic.

"That's what's going to win this campaign — that permanent place in your heart that this place holds," Peterson said.

For four days, the institute-led group explored Coyote Gulch and lower Escalante Canyon. The retreating water has revealed seeps and springs, alcoves carpeted with maidenhair fern and columbine, quiet pools reflecting burnished slickrock. It also has revealed discarded tires and towering deposits of sediment.

Already, the flowing water has cut deeply into those layers of mud and begun moving them downstream in a small-scale demonstration of natural reclamation.

Upstream in areas never touched by the reservoir, hikers were offered additional reminders of what drowned when the reservoir filled: whispering groves of cottonwood and willow trees, grassy flats where Anasazi farmers — their abandoned granaries and rock art still visible high on the cliffs — grew corn, beans and squash hundreds of years ago.

Defenders of the dam are adamant that it is a key component in the water and power system of the West. "If there ever was a period of time that demonstrated the critical nature of and need for Lake Powell, now is the time," said Barry Wirth, regional public affairs officer for the U.S. Bureau of Reclamation. "Without Lake Powell, without Lake Mead, without the Colorado River Storage Project, we wouldn't have made it to this point."

When they left Coyote Gulch after four days of exploration, Corkrum and his group of backpackers didn’t talk much about kilowatt-hours or acre-feet. They dawdled on the rim after the long climb up from the river as if mesmerized by what they had seen. Butler pointed to sections of the canyon far below that would vanish beneath stagnant water if the reservoir were to fill again. "Tell the world about it," he said.

John Krist, a writer in Ventura, California, is a contributor to Writers on the Range, a service of High Country News in Paonia, Colorado (hcn.org).