The trails of Tuolumne Grove, a popular site in Yosemite National Park, wind through forests of pine and giant sequoias, the largest trees on earth.

On July 19, after hiking about a mile into the grove, Ms Angela Lin, 29, and her friends heard a snapping sound above them.

“Two to three seconds later, branches fell out of the sky,” Ms Lin’s friend, Mr David Hua, told SFGate.

“One big branch struck Angela and then there were a bunch of smaller ones directly behind me.”

Mr Hua said he closed his eyes as the branches crashed down.

When he opened them, he saw Ms Lin on the ground, blood pooling around her head. He called 911 and performed cardiopulmonary resuscitation until a ranger took over.

This week, the Tuolumne County Sheriff’s Office released a statement about the incident, identifying Ms Lin and saying that an autopsy had determined that her death was accidental, resulting from blunt injuries.

It said a ranger had responded at about 6pm that day after reports that a hiker had been fatally struck by “falling portions of a tree”.

The news has generated interest in the accident, a rare occurrence along a popular trail in one of the nation’s busiest national parks. News reports have focused on the allure of venturing into the wilderness despite its potential risks.

Falling branch deaths are uncommon but not unheard-of. Two campers died after a branch fell on their tent in Yosemite in 2015.

Ms Angela Shih Lin was born in Los Angeles, but lived in Mountain View, California, according to a memorial notice.

She worked at Google as a software engineer, according to her LinkedIn profile. The company said in a statement that it “lost a loved and respected member of our team.”

Mr Hua and Ms Lin’s family did not respond to requests for comment.