College student Grace Rohloff slips and falls 200ft to her death in front of her horrified dad while hiking Yosemite's Half Dome cables

A college student who slipped and fell to her death while hiking in Yosemite with her father said, 'dad, my shoes are slippery' seconds before she plummeted.

Grace Rohloff, 20, plunged 200 feet down the treacherous Half Dome after she lost her footing while descending cables on the cliff.

She and her dad Jonathan Rohloff are both experienced hikers but had slowed their descent to accommodate less experienced climbers and ended up getting stuck in a rain storm.

Rohloff watched in horror as his daughter tumbled down the sheer rock face near the end of the descent on July 11.

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

He immediately scrambled down after her, but was unable to get down the steep mountain where the University of Arizona student had come to a rest.

Desperately hoping for a miracle, he began shouting: 'Grace, I'm here. I'm not going to leave you. If you can hear my voice, give me a sign. I love you.' 

But it was an agonizing three hour wait until rescue teams could reach Grace, who had suffered a catastrophic head injury.

'It was one of the most heartbreaking things I've ever seen,' hiker Erin McGlynn said.

McGlynn, 20, was among the other hikers who encountered Rohloff as he was frantically praying for his daughter's safety.

'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,' she added.

The father and daughter were experienced hikers who had long dreamed of completing the Half Dome, which only allows 300 hikers a day to summit.

They were ecstatic to be one of the lucky few granted a permit to undertake the journey on that fateful day.

As they headed out they were warned of a storm, but it appeared clear overhead even as they headed up a 400 foot stretch of cables to the summit.

Shortly after summiting, a storm began brewing and they began to make their descent.

'A black cloud was rolling in like gangbusters,' Rohloff 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 father and daughter could easily have traversed down, but got trapped behind another set of climbers and didn't want to seem rude by passing them.

But as the seconds ticked by the storm only grew in strength until they were descending in perilous conditions.

'Dad, my shoes are so slippery,' he recalled her saying as they agreed to take things carefully. 

They were three quarters of the way through when Grace's new hiking boots began to slip and her feet went out from under her.

Rohloff was forced to watch helplessly as she plunged down and could only hope she was still alive. 

'I just wanted to get my daughter,' he recalled as he told how he raced down the remaining cables.

After calling 911, Rohloff began to to pray along with other hikers who had witnessed the horror.

Park ranger Shawna Daly attended to him, waiting by his side in the howling wind and freezing hail until a rescue helicopter could retrieve Grace.

Rohloff praised the ranger for going 'above and beyond' to try and console him. 

He explained he also took comfort in hearing from a coroner that Grace likely died during the fall. 

'If she was gone, that she didn't have to suffer,' he explained, adding that he hopes park rangers can recover his daughter's backpack which contains the last photos she took on the trip.

Rohloff also paid tribute to his daughter's, 'beautiful soul' as he recounted the horror of their final day together.

'She was the star on every team she ever played on, but the 12th girl on the basketball team — Grace made that girl feel just as important,' Rohloff said. 'She had a way of connecting people and making them feel special.' 

Her mom Astraea Rohloff described her daughter as, 'pure joy', explaining she would always do her best to make others feel good.

'Just being with her ensured that you were getting a little better day,' she said, 

Grace's cousin Emily Samora, who was due to head on a camping trip with her this summer, said she, 'brought light to so many lives'. 

Tragically, Grace's story is not an isolated incident and since 2006 at least six people including the student have died after rainstorms made Half Dome's surface slippery.

In 2010, the park instituted the cap on hikers who could summit every day. However, this only increased incidents as those who received a permit became determined to reach the summit despite any potential risks.

Rohloff would like park officials to bring in more features to make the cables safer such as a second set added lower to the ground and wooden planks that allow hikers to step from one to the other.

He confirmed that he will never hike the 'unnecessarily dangerous' stretch again but hopes measures can be implemented to prevent a further tragedy.