Visitors to Grand Canyon National Park are being warned of another round of extreme temperatures expected early next week following a series of heat-related incidents that included the deaths of three hikers.

The National Weather Service (NWS) issued an extreme heat watch for midday Monday through Tuesday, forecasting temperatures that could reach or exceed 110 degrees Fahrenheit (43 degrees Celsius) in lower elevations such as Phantom Ranch.

Why It Matters

The warning comes after two incidents on June 12 and June 16 involving hikers in the park’s inner canyon, including a 72-year-old man and two others, ages 67 and 68, who were later found dead on separate trails.

What To Know

Park officials said the recent deaths appear to be linked to heat-related illness and are part of what the National Park Service described as a “recent influx of heat-related incidents.” Visitors are being strongly advised to avoid hiking during the hottest parts of the day.

The fatalities occurred in the inner canyon, where temperatures can far exceed those recorded at the rim. Officials note that conditions at lower elevations can be 20 to 25 degrees hotter than at the top, making the heat more dangerous than it may initially appear.

According to the National Park Service, the first victim became ill on June 12 while hiking the South Kaibab Trail and died before rescue crews could reach him. Four days later, a 67-year-old man and a 68-year-old woman were found dead on the North Kaibab Trail, which officials describe as one of the park’s most difficult routes.

Despite rapid response efforts, including aerial support, all three hikers were dead by the time emergency personnel arrived. Their bodies were taken to the Coconino County Medical Examiner’s Office, and investigations into the deaths remain ongoing, according to officials.

Heat Increases After Descent Into the Canyon

The extreme heat warning highlights the dangers facing visitors during peak summer conditions, particularly in the inner canyon, where temperatures can surpass 109 degrees Fahrenheit even in shaded areas.

Officials say hikers may underestimate the risks because the descent into the canyon often begins in relatively cooler conditions. However, temperatures rise significantly as visitors move deeper into the canyon, and the return ascent involves strenuous climbing in hotter conditions.

“It’s just a hot place at the bottom of the Grand Canyon,” said Justin Johndrow, a meteorologist with the National Weather Service in Flagstaff, Arizona. He noted that the region is approaching its hottest period of the year before cooler monsoon conditions arrive later in the summer.

Authorities are urging visitors to avoid hiking between 10 a.m. and 4 p.m., when temperatures are at their highest, and to take additional precautions such as carrying enough water and planning trips carefully.

The warnings come as much of the western United States experiences above-average temperatures, with further heat expected in the coming days. Officials also cautioned that the combination of prolonged dry weather, high temperatures and low humidity is increasing the risk of wildfires across the region.

Grand Canyon National Park, one of the most visited in the United States, draws millions of visitors each year. Park officials emphasized that while hiking is a popular activity, conditions during extreme heat can quickly become life-threatening, even for experienced hikers.

Recognizing Heat Exhaustion and Heat Stroke

This story contains reporting from the Associated Press.