The fatal fall Thursday from the closed Castle Trail high in Punaluu Valley is at least the third such death of a hiker traveling on an off-limits trail in the last two years.

Authorities said Friday the accident is a reminder that trails closed to the public can be especially dangerous.

“These incidents are examples of why people need to reconsider going on trails that are not maintained or managed for public use, and which might be closed for safety reasons,” said Deborah Ward, spokeswoman for the state Department of Land and Natural Resources.

On Thursday a 29-year-old male hiker fell 300 feet to his death. The Honolulu Fire Department responded at about 7 p.m. Thursday after hearing from a group of six hikers from Oahu that got separated from a fellow hiker and were worried he may have fallen.

Firefighters, including the department’s Air 1 helicopter, found the body at about 10:49 p.m., said HFD spokesman Capt. David Jenkins.

Air operations were then suspended due to rainy and windy conditions. Three firefighters stayed with the hikers and sheltered in place overnight.

The helicopter crew resumed operations at dawn Friday morning, and the hiker’s body was airlifted to a landing zone off of Green Valley Road in Punaluu. The six other hikers, who were uninjured, were also airlifted from the trail, Jenkins said.

During the rescue the Fire Department received another distress call about two hikers trying to find their way to the closed Haiku Stairs, also known as Stairway to Heaven.

The Fire Department deployed its Air 2 helicopter to the area. Jenkins said they airlifted the hikers, a man and woman described to be in their 20s, to Kaneohe District Park. There were no reports of injuries.

Jenkins said mountain rescues are a growing phenomenon on Oahu due to the increasing popularity of wilderness hiking fueled by internet adventure websites.

Crews have responded to 51 mountain rescues through the first three months of this year, he said, after making 260 rescues in 2016 and 187 rescues in 2015.

“It’s beautiful. These are outstanding views,” he said. “You can’t keep a good thing secret very long.”

But even the most well-maintained mountain trail can be dangerous, especially for hikers who are not prepared or physically capable, the captain said.

That last death from an unauthorized trail was Dec. 24, when 22-year-old Moanalua High School graduate Kaisha Chu fell 200 feet to her death from Puu Manamana Trail in Kaaawa, a trail notorious for being one of the most dangerous on the island.

Four years ago another hiker, Elizabeth Tarpey of Kapolei, died after falling 300 feet from the same trail.

Two years ago Darlene Feliciano, a manager at the Keeaumoku Street Walmart, fell 500 feet to her death from the closed Makapuu Tom Tom trail above Sea Life Park.

Ward said the state recommends hikers use the trails that are maintained for public use, including those listed on the Na Ala Hele Trails and Access Program website at hawaiitrails.org.

According to Marigold Zoll, Oahu branch manager of the state Division of Forestry and Wildlife, the Castle Trail would be considered difficult for most folks since it is unmaintained, makes a significant climb in elevation and is extremely steep and narrow in sections.

An upper portion of the trail is on state land that used to be part of Sacred Falls State Park, which was shut down in 1999 after a fatal rockfall incident, Zoll said. In 2014 the upper portion of the valley was removed from the state park and incorporated into the Kaluanui Natural Area Reserve.

“Access to the state-owned portion of the Castle Trail is difficult, remote, unmaintained and not recommended for the general public,” Zoll said in a statement. “Unstable weather conditions and topography make rescue operations extremely dangerous to public safety personnel.”

Most of the Castle Trail is owned by Kamehameha Schools.

Spokesman Kekoa Paulsen said Kamehameha Schools offered assistance to authorities in their rescue and recovery efforts and is awaiting information to answer further questions relating to “this sad and unfortunate accident.”

In 2014 and 2015 Kamehameha Schools formally urged website publishers to remove information about closed and dangerous trails on other property owned by the schools.

Randy Ching, a veteran hiker, trail builder and executive committee member with the Sierra Club of Oahu, said all of Oahu’s trails — public and off-limits — are being overrun by hikers.

“I’m very, very concerned that Oahu’s hiking trails are being loved to death. There are too many people and not enough maintenance being done,” he said.

Ching said he fears that residents and neighbors of popular trailheads will pressure landowners into closing even more trails across the island.