5. Heat Stress
A formidable threat in the Southwest, this killer strikes with extreme force, though not without ample warning.
On 9 a.m. on Thursday, July 8, 2004, 24-year-old Margaret Bradley and a male companion left the Grand Canyon’s South Rim for a 27-mile trail run. Their plan was to descend the Grandview Trail to the Tonto Trail, cross 16 miles of hot, rolling plateau, then climb 3,200 feet in 5.5 miles back to the rim on the South Kaibab Trail.
That spring, Bradley had finished the Boston Marathon in 88°F heat, placing 31st among women with a time of 3 hours, 4 minutes. Anticipating a similar effort, the duo was traveling light. Bradley’s partner (authorities refuse to name him) carried a gallon of water; she had 1.5 liters. There are no water sources along the route, and neither carried maps or headlamps.
By 3 p.m., the temperature had reached 105°F and the pair had covered only 12 miles. On the exposed plateau, their run turned into a walk. Soon, the man crawled under a bush, unable to continue. Bradley went on for help.
Around dawn, the man woke to cooler temperatures and pushed on. As he neared the South Kaibab Trail, he encountered a USGS employee with a satellite phone, who called rangers for directions to an emergency water cache. Inexplicably, the companion never mentioned Bradley. “In all the confusion,” says Grand Canyon SAR Coordinator Ken Phillips, “he assumed she had gotten out of the canyon.”
Bradley wasn’t reported missing until Saturday morning. At 2 p.m., a helicopter spotted her body 300 feet below the Tonto Trail in the Cremation Creek drainage. She was curled in a fetal position, a casualty of acute dehydration and heatstroke. Like all too many Grand Canyon fatalities, Bradley was apparently trying to reach the river, only to be stymied by unbroken cliff bands.
“She had descended several small pouroffs,” explains Phillips. “The last one, a water-polished slickrock trough, was high enough and tough enough she couldn’t get back up.” Authorities estimate she had died 12 to 24 hours before being found, as many as 30 hours after her companion had reached a satellite phone.
“We do about 300 rescue missions a year,” says Phillips. “About 80 percent are related to heat.” Most victims are either new to the desert, too ambitious, or forced by circumstances to move midday.
The result is one of four conditions:
1) Heat exhaustion, where dehydration leads to acute fatigue and potential organ failure.
2) Heatstroke, a life-threatening rise in core body temperature.
3) Hyponatremia, a dangerous combination of heavy sweating, high water consumption, and low salt intake that leaches electrolytes from the body, leading to seizures; and 4) exertional rhabdomyolysis, the breakdown of muscle fibers from exertion and heat, which releases myoglobin that clogs the kidneys and leads to renal failure.
- Train for heat In just several weeks, you can adapt your body to extreme hot weather. Go to badwater.com/training to learn about proven techniques developed by ultramarathoners, including exercising in a sauna, driving in summer without air conditioning, and running in heavy fleece layers.
- Lose weight Obesity exacerbates all forms of heat illness.
- Stash water Not sure if you’ll encounter a stream or spring on your hike? Take half a day to drive and/or hike extra water into one or more locations along your intended route; 8 liters a day is wise for a hot climate.