A 55-year-old Virginia man died in the Grand Canyon while trying to hike 21 miles from the South Rim to the North Rim in a single day, authorities said Monday.

Grand Canyon National Park officials identified the hiker who died Saturday as Ranjith Varma of Manassas. The location where he passed away is toward the end of the South Rim to North Rim trek, which can take 12 to 15 hours to complete.

At around 2 p.m. Saturday, the Grand Canyon Regional Communications Center reported receiving an emergency call of a hiker in distress on the North Kaibab Trail, about one mile south of Cottonwood Campground. Varma became unresponsive, and bystanders and rangers both unsuccessfully tried to resuscitate him, park officials said.

It wasn't immediately clear if his death was heat related. An investigation was being conducted by the Park Service and the Coconino County Medical Examiner.

The high temperature on Saturday was 87 degrees at Grand Canyon Airport, which is about a 20 minute drive from the South Rim.

Earlier this year, a 36-year-old Indiana woman died while trying to hike to the Colorado River and back in a day. She was found unconscious on May 14 along the Bright Angel Trail above the Three-Mile Resthouse.

On July 3, a 57-year-old woman died while on an eight-mile hike in triple-digit heat at Grand Canyon National Park.

Park officials say summertime temperatures on exposed parts of the trail can reach over 120 degrees, so they urge the public not to hike in the inner canyon between the hours of 10 a.m. and 4 p.m.

"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," officials said Monday.

Last month, a 34-year-old woman who went missing on a hike in Arizona was found dead, and it appeared to be heat-related, authorities said.

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