Three hikers have died at Grand Canyon National Park in Arizona due to heat-related illnesses as temperatures surged past 100 degrees. The incidents occurred across two separate cases, according to the National Park Service.

Authorities found a 67-year-old man and a 68-year-old woman deceased on the North Kaibab Trail, which is considered among the most challenging inner canyon trails. Earlier, a 72-year-old man died on the South Kaibab Trail. This trail is known for its panoramic views but offers little shade and lacks water access.

The identities of the victims have not been disclosed. Earlier in the month, another fatality occurred when an 18-year-old experienced heat-related symptoms at the park.

The Park Service highlighted the risks of hiking during the high temperatures of summer, stating that the recent increase in heat-related incidents illustrates the dangerous levels that Inner Canyon temperatures have reached. These conditions can overwhelm hikers, especially during the hottest parts of the day.

Temperature variations occur in the park due to elevation changes. As hikers descend, conditions become hotter. Meteorologist Justin Johndrow from the National Weather Service in Flagstaff described it as hiking a mountain in reverse.

Specific details regarding the elevation where the hikers were found or the times they were hiking remain unclear. Park Service representatives have not provided comments. Temperatures at the canyon’s bottom reached 112 degrees on the day two hikers were located and 109 degrees the previous week. These levels were above average of around 103 and 101 degrees for those days, respectively.

The Park Service advises visitors to avoid all hiking activities between 10 a.m. and 4 p.m. when temperatures peak.