It's not just Death Valley...

"Arches National Park (UT)
High Temperatures Cause Series Of Heat-Related Emergencies

The park experienced a series of heat-related medical emergencies involving seven visitors and one employee within a period of just over 24 hours last weekend. High temperatures both days were in the 100 to 104 degree range. Of this total, three were taken by ambulance to a local hospital and a fourth was flown to another hospital in Grand Junction. The remaining four were treated and released.

Just before 2 p.m., on Saturday, July 12th, rangers received a report of a woman having a heart attack on the Delicate Arch viewpoint trail. The first rangers to arrive were unable to find her on the trail, but were soon flagged down by the occupants of a vehicle near Wolfe Ranch. Two men inside who’d just come off that trail were suffering from heat exhaustion. They were treated by park personnel and Grand County EMS.

Around 8:30 that evening, a report was received of an unconscious man near Delicate Arch. Park, Grand County SAR and Grand County EMS personnel responded, hiking a mile and a half up from the trailhead. The man was treated for heart issues arising from heat stroke throughout the rescue and litter carryout. He was taken to Moab Regional Hospital

EMS incidents resumed the following afternoon when rangers received a report of an unconscious man near Delicate Arch. Park and Grand County personnel again responded, treated the man on scene, and littered him out to the trailhead. He refused further treatment and transportation to the hospital.

While the above rescue was in progress, an interpretive ranger preparing for a guided hike reported coming up an unconscious man in the Fiery Furnace parking lot. The responding ranger found an incoherent man with tingling in his arms and legs. A woman in the car was suffering from severe headache and cramping. Both were taken by ambulance to the hospital.

A third EMS emergency was reported while the above incidents were underway. Around 4:30 p.m., the same ranger who’d called in the above incident was leading the guided hike when a visitor collapsed. The ranger reported that the woman was unconscious and that she could not obtain a radial pulse. EMS personnel who were still in the Fiery Furnace parking lot headed down the trail. The woman was assessed and found to be suffering from heat stroke. She was flown by helicopter to St. Mary’s Hospital in Grand Junction.

Finally, at the conclusion of the Delicate Arch carryout, one member of the park SAR team was treated on scene for heat exhaustion."

While many visitors to parks are savvy, a certain percentage are totally clueless about hazards and routine precautions. The range from well equipped to zilch is amazing.