A 20-year-old woman is dead after slipping and falling approximately 200 feet while hiking Yosemite’s treacherous Half Dome.

Grace Rohloff, an experienced hiker, was on a 16-mile hike with her father Jonathan Rohloff when the tragedy occurred.

“She just slid off to the side, right by me, down the mountain,” Jonathan told SF Gate. “It happened so fast. I tried to reach my hand up, but she was already gone.”

The father-daughter duo were avid hikers, so when Grace was able to secure a permit to hike Half Dome through a lottery system, the pair drove from their home in Arizona to Yosemite National Park in California for their big adventure.

On the day of their hike they were warned about the threat of thunderstorms, but four hours later, by the time they reached Half Dome’s famous cables the sky had cleared.

Grace and Jonathan only had a few moments to enjoy the view from the top before a loud thunderclap filled the sky.

“A black cloud was rolling in like gangbusters,” Jonathan said. “I was like, ‘We have got to get down now, because we don’t want to be up here with any rain. It rolled in literally out of nowhere.’”

The two began making their way down the trail.

Unfortunately, due to other hikers proceeding with caution, Grace and Jonathan got caught in the rainstorm while on the cables. It was a recipe for disaster. Everyone started to slide on the slippery rock.

Although Grace wore new shoes meant to have better traction, she felt her feet slipping.

“Dad, my shoes are so slippery,” Jonathan recalled her saying.

He attempted to reassure her that everything would be okay, but when they were nearly at the bottom of the cables Grace’s feet slipped out from under her and she fell down a slippery steep slope.

While calling out for his daughter, Jonathan rushed to the bottom of the trail as fast as he could.

“I just wanted to get my daughter,” he said, hopeful that she was still alive.

“Grace, I’m here. I’m not going to leave you. If you can hear my voice, give me a sign. I love you,” he repeated over and over.

Jonathan was forced to wait an agonizing three hours for a rescue team to come in with a helicopter to retrieve his daughter’s body. As he waited for officials, Shawna Daly, a park ranger, sat with him through the intense storm and comforted him.

He later learned Grace suffered a severe head injury and likely died as she fell down the mountainside.

“That was at least comforting,” he said. “If she was gone, that she didn’t have to suffer.”

“It was one of the most heartbreaking things I’ve ever seen,” Erin McGlynn, 22, said. McGlynn encountered Jonathan on the trail after climbing to the top with her mom.

“But it was also one of the bravest things I’ve ever seen. He was able to compose himself, just in case he could provide any comfort to her. He did everything he possibly could have.”

Rest in peace, Grace. You will never be forgotten.