Officials at Yosemite National Park say a 26-year-old woman fell 600 feet to her death while climbing Half Dome over the weekend.
The woman was identified Monday as Hayley LaFlamme of San Ramon.
Park spokeswoman Kari Cobb says LaFlamme was hiking with three friends Sunday when she slipped on wet rock while descending the enormous granite dome around noon.
A severe lightning, thunder, and rainstorm was present in the valley throughout the morning Sunday, according to park officials.
LaFlamme fell on the shoulder of the dome where the cables end that help hikers navigate the final ascent. She was pronounced dead at the scene.
An investigation is underway, but Cobb says rain likely played a factor by making the granite slippery.
Sunday's was the 14th fatality this year in the park, which normally averages between five and six by August.
Last month, three people were swept to their deaths when they entered the Merced River above the 317-foot Vernal Fall.
Their bodies have not been recovered and are feared to be trapped under rocks at the bottom of the river bed.
The last hiker who died on Half Dome was also from San Ramon. Majoj Kumar fell to his death on June 13, 2009.