Father whose daughter suffered fatal fall on Half Dome speaks out

Jonathan Rohloff, father of Grace Rohloff, called the moment his daughter fell to her death while hiking the Half Dome trail in Yosemite National Park "pure terror."

Jonathan Rohloff opened up to "Good Morning America" on Sunday, calling for change after his daughter slipped and fell to her death while they were hiking the bucket list trail together.

"It was just the two of us, and we set out in the morning," he said. "It's about [a] ...16-1/2-mile hike from the trailhead, but we had parked a little ways away from that."

Jonathan Rohloff, who had hiked several trails with his daughter previously, said she shared a mutual interest in the activity and had won a lottery to permit the hike. Their repertoire of trails included the Bright Angel trail in the Grand Canyon , the Colorado River and nearly all the trails in Arizona.

"We got to the top," he said, recounting the duo's Half Dome hike. "We took a few pictures, and then I heard a loud thunderclap from behind me, and I turned around. And I'm like, all right, this storm's coming in fast."

According to Jonathan Rohloff, the storm intensified as they descended the mountain.

"It was very unstable, and so we were just like, 'OK, let's just take it one board at a time,'" he said.

According to Jonathan Rohloff, Grace Rohloff lost her footing, sliding down 250 feet and sustaining a fatal head injury.

"Ten minutes before she went down, she was smiling ear to ear, happy as can be, you know, hugging me, loving, telling me she loved me and telling me how this was something she'd [wanted to] do for so long and just pure bliss," he said. "Ten minutes later, it's just -- it was a tragedy to know that she passed away."

Jonathan Rohloff said he was sharing his daughter's story to advocate for a safer cable system on Half Dome. He said the park needs to do more to improve safety, including adding more wood slats on the trails and taking weather conditions into account when issuing passes.

According to the National Park Service website, the "most famous -- or infamous -- part" of the Half Dome hike is the ascent up the cables.

"The two metal cables allow hikers to climb the last 400 feet to the summit without rock climbing equipment. Since 1919, relatively few people have fallen and died on the cables."

ABC News has reached out to Yosemite National Park for comment but has not received a response.