YOSEMITE NATIONAL PARK — The rumble began high on the sheer cliff wall, like faraway thunder before a storm.
A slab of granite as big as a railroad boxcar had let loose 1,300 feet up Glacier Point's age-worn face. The million-pound rock cartwheeled and shattered, tracing a plume of dust downward toward Peter Terbush.
In his last earthbound moments, Terbush turned to a long-ago climbing lesson taught by his dad. As a little boy first astride a mountain, he learned to always protect a partner at the end of the rope. Never let go.
The broad-shouldered 21-year-old held fast to the nylon lifeline lashed to a friend 60 feet up. Another buddy on the ground scrambled for cover as the boulders hit earth, exploding like bombs.
Fate let his two friends escape with lacerations. They found Terbush's body crumpled in a ball, his hands still gripping the rope.
Six years after the rock slide, his parents suspect that mankind's handprint atop Glacier Point -- most notably a bathroom water system prone to overflow -- lubricated the cliff face, provoking a flurry of rock falls, including the June 1999 tragedy that claimed Terbush.
His parents have poured their grief and suspicions and search for answers into a $10-million wrongful death lawsuit against the National Park Service. "My son understood the risks of climbing," said Jim Terbush, himself a climber. "But he didn't know the conditions on Glacier Point had been fundamentally changed."
The legal battle, set for a first hearing Tuesday, has sent reverberations around Yosemite and the climbing community beyond.
Park officials have a ready argument -- and an admonition: No one can know when a rock fall is going to happen. And a ruling against the park, they warn, could all but kill climbing in the Yosemite Valley.
Climbers contend their sport is the ultimate test of personal responsibility. The lawsuit goes beyond geology and public policy. To climbers, it challenges a basic tenet.
"We're at risk every time we go up," Sean Kovatch, 20, said recently during his first Yosemite climbing trip. "And sometimes people don't come off the mountain."
Skinny but Strong
Peter Terbush seemed destined to stand beside a cliff face.
Born into the third generation of a Colorado climbing family, he nearly didn't make it into diapers. Arriving unexpectedly 14 weeks premature on a snowy night at home in Castle Rock, Terbush survived a harrowing drive to the emergency room.
He was all of 1 pound, 14 ounces, and the doctor wrapped him in tin foil to keep him warm for transport to a bigger hospital. He looked, his father recalled, like a little baked potato.
Pete grew up skinny but strong, a ball of positive energy with a floppy mop of curly auburn hair topping it all.
He took up the family avocation, learning to climb with his dad at age 9. With his owlish glasses and sideways smile, he looked like a Harry Potter of the hillside. He even launched his own climbing club in elementary school, proving precociously adventurous. One after-school climb ended with his being rescued by his dad and the Castle Rock Fire Department.
Jim Terbush was a physician for the U.S. Navy and at American embassies from London to Singapore. As the family journeyed to the corners of the world, Peter Terbush was always in the mountains. He climbed in the Himalayas, the Dolomites, the French Alps.
Back in the United States, Terbush attended Western State College in Gunnison, Colo., where he majored in geology and built an inseparable cadre of friends who thought nothing of driving 10 hours to Zion National Park for a weekend of climbing, returning exhausted just in time for Monday classes. In winter they'd go skiing, Pete dressed in old leather boots and wool knickers, using old-school poles and singing the whole time.
"He would bounce when he walked," remembered Laura Chase, a close friend. "His hair would bounce. All this electricity would bounce through his hair."
By 21, he had lost that little boy look. He grew a beard and developed the lean muscularity intrinsic to climbing, sometimes grabbing the narrow crest of a doorframe and practicing pull-ups, more to strengthen fingertips than to build biceps.
He taught climbing classes, earning a reputation for skill and safety. "Good skills!" he'd yell to climbers displaying a nice bit of technique. He talked endlessly of becoming a climbing guide. But he knew something was missing -- a trip to Yosemite, one of the climbing world's crucibles.
A Late Climb
His last few days of life were spent mostly on flat terra firma.
He and a few college buddies tried scaling El Capitan, but an equipment failure prompted a retreat. Instead, Terbush and Joe Kewin hiked in the ethereal beauty of the Yosemite high country. They basked in meadows hugged by salt-and-pepper granite hills, took in the saw-tooth fusion of rock and sky.