A backpacker is believed to have died from extreme heat in Grand Canyon/NPS file

Heat is believed to have killed a backpacker at Grand Canyon National Park, just one of several deadly incidents in the National Park System in recent days.

The Grand Canyon hiker, 53-year-old Michelle Meder, of Hudson, Ohio, was on a multi-day trek from the Hermit Trail to Bright Angel Trail when she became disoriented and then fell unconscious on Saturday, a park releaase said. On Sunday, rangers who responded to the matter determined that Meder had passed away. The high temperature at Phantom Ranch on the floor of the national park reached about 115 degrees on Sunday, according to the park.

The incident prompted rangers again to warn visitors to Grand Canyon, and especially those who planned to hike down from the South or North rims, to be prepared for excessively hot days in the coming weeks. During summer months temperatures on exposed parts of the trail can reach over 120°F (49 °C) in the shade. Hiking trails at the park do not close due to hot weather. But rangers advise against hiking in the inner canyon between the hours of 10 a.m. and 4 p.m. Most of the people who need emergency medical help in the canyon due to heat illness are hiking between these hours, a park release said.

Hiking in extreme heat can lead to serious health risks including heat exhaustion, heat stroke, hyponatremia, and death. Be aware that efforts to assist hikers may be delayed during the summer months due to limited staff, the number of rescue calls, employee safety requirements, and limited helicopter flying capability during periods of extreme heat or inclement weather.

At Rocky Mountain National Park in Colorado, rangers were notified late Friday afternoon that a woman’s body was discovered below the outtake of The Loch, a backcountry lake. The body was noticed by park visitors in the drainage below the outlet of The Loch. Park rangers attempted to reach the location Friday night, but lightning storms and darkness hampered those efforts. On Saturday, park search and rescue team members were again hampered by weather while conducting field operations. On Sunday, 28 RMNP Search and Rescue Team members were able to bring the woman's body up 60 feet through steep, rocky, hazardous terrain to the Loch Vale Trail, and then wheeled the body out by litter to the Glacier Gorge Trailhead.

Her body was transferred to the Larimer County Coroner/Medical Examiner’s Office. She has been positively identified as a 33-year-old female from Arvada, Colorado, a park release said.

A death also was reported in the past week at Bighorn Canyon National Recreation Area in Wyoming. Nineteen-year-old Dominic Hunder, of Lovell, Wyoming, had been swimming with friends near Barry's Landing in the NRA on Friday when he disappeared underwater. Searchers found the young man's body underwater around 2:30 p.m. on Saturday.