A woman and her father were found dead Friday afternoon at a national park in southeastern Utah, where they’d run out of water as temperatures soared, officials said.

The 23-year-old woman and 52-year-old man from Green Bay, Wisconsin, were hiking in Canyonlands National Park when their water ran out, the National Park Service said in a news release. Neither were identified by name.

They had gotten lost along the park’s Syncline Trail, a route that covers more than eight miles from end to end and typically takes between five and seven hours to complete. The looped trail’s difficulty level is marked “strenuous” by the park service, which notes in a description of the hike that it involves a steep elevation change of around 1,500 feet and “requires navigating steep switchbacks, climbing and scrambling through boulder fields where trail markers are few and far apart.”

Temperatures topped 100 degrees Friday in Canyonlands, park officials said. The hikers’ deaths came in the midst of an intense heat wave that touched most of Utah last week into the weekend, breaking temperature records in some places and prompting warnings from the National Weather Service about the potential for heat-related illnesses.

The National Park Service provided few details about the circumstances around their deaths but said that a local police dispatcher received a 911 text on Friday afternoon that tipped them off to the pair’s situation. Rangers and authorities from other agencies in the area initiated a search for the father and daughter, who were already deceased by the time they reached them. The park service said it is investigating the incident along with the San Juan County Sheriff’s Office.

“While temperatures remain high this summer, park visitors are advised to carry and drink plenty of water and avoid strenuous activity during midday heat,” the park service said.

Extreme heat across the United States this summer has been tied to deaths in other parts of the country, too. Less than one week before the hikers died in Utah, officials blamed scorching temperatures for a motorcyclist’s death in California’s Death Valley, the Associated Press reported. The incident happened as Death Valley recorded a temperature high of 128 F. Around the same time, another person in the area was hospitalized because of heat exposure, according to AP.