The thrill of trying to reach the top of Half Dome at Yosemite National Park turned fatal on Thursday for a hiker who fell 500 feet from the famed rock face as she was scaling the steepest part of the trail, the authorities said.

The hiker, Danielle Burnett, 29, of Lake Havasu City, Ariz., was dead when park rangers reached her, according to a park spokesman, Scott Gediman, who said the accident was under investigation.

Ms. Burnett had been climbing a rigorous top section of Half Dome, one that uses a pair of fixed cables for hikers to hold onto, when she fell, officials said.

She was at least the 12th person since 1995 to die while hiking Half Dome, The Mercury News reported.

There have been dozens of search-and-rescue calls to Half Dome, where hikers have sought to follow in the footsteps of the naturalist John Muir and the photographer Ansel Adams. The massive rock soars to 8,800 feet above sea level and was pictured on the California state quarter issued in 2005.