Grand Canyon National Park — IT'S NEARLY NOON, AND THE MORNING'S HIKERS scramble out of the baking inner canyon, wheezing and dripping. In a room a few hundred yards from the South Rim, supervising ranger Marc Yeston touches a green pen to a wall map and traces a long, wriggling path. Then he makes a triangle.
Here, he says, is the spot where they found Margaret Bradley, a 24-year-old University of Chicago medical student and marathoner.
Just three months before, the 115-pound Bradley had finished the Boston Marathon in a few ticks over three hours, a solid performance in temperatures well over 80.
"I focused on keeping myself hydrated," she told the magazine Chicago Athlete afterward, "and not letting the adrenaline from the crowd make me do something stupid."
But last month, when she and a companion decided to try a 27-mile trail run in a single day, that caution was missing. A cascading series of miscalculations, say rangers, turned this scholar-athlete into the Grand Canyon's first dehydration fatality in four years.
Telling her story, rangers look to their feet, grope for words, trail off in midsentence. She was younger than most of them, and probably fitter. And now all that was left was an excruciating lesson in miscommunication and biochemistry.
In a single hour, a hiker in desert heat can easily lose a liter of moisture through sweat -- maybe, some experts say, as many as three liters (a liter is slightly more than a quart).
Without water, write authors Michael P. Ghiglieri and Thomas M. Myers in their book "Over the Edge: Death in Grand Canyon," dehydration, hyperthermia and exertion in the canyon can "turn people, inch by inch, into heat zombies.... Kids and young adults seem to run at full function in the heat, sweating appropriately and seemingly going strong, but abruptly, when dehydration kicks in, they crash quickly and often unexpectedly. And die."
Those threats are compounded by the shape of the land: Mountains rebuff the unfit and unprepared in short order, but the canyon -- "the upside-down mountain," locals say -- begins as a pushover, all downhill trail and mild temperatures at 7,000 feet. For decades, with signs, brochures and newsletters, rangers have struggled to make hikers understand the challenges that wait below.
These challenges are serious enough that the park created a special Preventative Search and Rescue unit seven years ago after a flurry of dehydration and heatstroke cases in the canyon. Most summer days, rangers station themselves a mile or two or three down the busiest trails, chatting up hikers as they pass, checking to see if fitness and water supplies match their itineraries.
But it's a tricky job, because rangers can't watch every trail and a ranger can't order a hiker off the trail for seeming unprepared. And at least once a day, says supervisor Bonnie Taylor, somebody defies her warnings and heads on down.
"Our job is not to harass them," Taylor says. "Our job is to understand that they understand the situation here."
Before she headed to college in Chicago, Bradley was raised in Falmouth, Mass. She hadn't spent much time in the desert. But she wasn't easily daunted.
At the University of Chicago, she had earned a double degree in biology and Earth sciences, then went on to med school. She played violin in the university symphony and worked summers at the Marine Biological Laboratory in Woods Hole, Mass. And as a runner, putting in up to 90 miles a week, she'd competed in Division III national championships and earned all-American status.
To prepare for the canyon, she ran in the hills around Flagstaff for a few days. She also found a running partner, a Flagstaff man in his late 20s or 30s with whom she shared a Chicago connection. On July 8, they agreed to take on the canyon.
Rangers interviewed this man. They say they are not accusing him of wrongdoing and have refused repeated requests to identify him, citing his privacy and saying Bradley's family asked them to omit his name from public accounts. (A Freedom of Information Act request by The Times is pending.) Bradley's parents declined to comment for this article.
At least part of the tale, however, can be gleaned from rangers who were there. By Park Service accounts, the runners began their day about 9 a.m. at Grandview Point, the highest spot along the canyon's South Rim, where the trail head is 7,400 feet above sea level, nearly 5,000 feet above the river.
Here is where the two runners made their first mistakes. They set off nearly four hours after sunrise, several hours later than rangers advise distance hikers to begin on summer days, and they were traveling dangerously light. Bradley's companion had four liters of water. She carried fruit, three protein bars and just two bottles of water (about 1.5 liters). They carried no maps, and Bradley apparently had no flashlight or headlamp.