SALT LAKE CITY (AP) — They left their two young children with relatives and set off to celebrate their fifth wedding anniversary at one of the most beautiful hiking destinations in the Southwest.

Months earlier, the luck of a draw had brought Anthony and Elisabeth Ann Bervel coveted hiking permits for The Wave, a region of richly colored sandstone patterns near the Utah-Arizona border.

But just hours into Monday’s trek, 27-year-old Elisabeth Bervel died of cardiac arrest, becoming the third hiker in a month to succumb to the brutal summer heat and disorienting open country where no marked trail shows the way.

The deaths have prompted officials to reassess the dangers for people who make the hike and perhaps seek an outside investigation of the risks, said Kevin Wright, manager of Vermilion Cliffs National Monument.

“We’re considering everything at this point,” he said.

Only 20 hikers are granted permits each day, a limit defended as necessary to protect the rock formations and preserve a sense of wilderness around the signature rock formation said to be one of the most photographed spots in North America.

Hikers are given plenty of warnings about how to survive. They also get pictures of prominent landmarks and access to eight guides who can lead the way.

“It’s not like going to Zion National Park and hiking on an asphalt trail,” said Kane County sheriff ’s Sgt. Alan Alldredge. “Once you hit the slickrock, nothing distinguishes the trail.”

“It seems to go well for people going to The Wave,” he added. “But for some reasons on the way back, they end up getting lost.”

The Bervels, of Mesa, Ariz., lost their way on a three-mile cross-country route back to a trailhead, forcing them to spend extra hours under blazing sun in 90-degree temperatures and humidity, he said.

Officials said Elisabeth Bervel’s legs gave out hiking in soft sand, and her husband kept going to find a cellphone signal to call for help.

He appeared to be in no danger from the heat or exertion. But Kane County officials said he was distraught when he sat down Monday night to recount the tragedy. A phone listing for Anthony Bervel had been disconnected Tuesday.

“This event once again demonstrates the inherent risks associated with hiking in southern Utah’s desert country,” the Kane County Sheriff ’s Office said in a statement. “Even though the Bervels had tried to make sure they were prepared for this hike, the elements proved to be stronger.”

The latest death led to further questions about the lottery system that makes it hard to land a permit for the hike that starts in Utah before reaching The Wave in Arizona. More than 48,000 people applied last year for 7,300 available permits, officials said.

Half of the 20 daily permits are doled out on a walk-in basis at a visitor’s center in Kanab, with as many as 100 people showing up to get a permit for the next day.

The rest are awarded through an online lottery, with winners given a specific hiking date months in the future. For many, it’s a lifetime opportunity, and the difficulty in getting permits prompts some people to go in the heat of the summer.

On July 3, Ulrich and Patricia Wahli of Campbell, Calif., were found dead in 106-degree heat.