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, Angela Lin, 29, and her friends heard a snapping sound above them.

Tuolumne Grove is home to about two dozen mature giant sequoias and is a popular destination in Yosemite. The area was temporarily closed after the incident.

On the afternoon of July 19, a 29-year-old Google software engineer named Angela Lin was doing one of the things she loved most - hiking in Yosemite National Park. With her boyfriend and two friends,