Yosemite National Park, located in the Sierra Nevada mountains in California, is known for its spectacular granite peaks, waterfalls, and giant sequoia forests, attracting numerous visitors every year. On Monday, August 3rd, the park issued a warning to visitors concerning their safety.
Officials at Yosemite National Park reminded visitors of the potential dangers they may face during summer visits. The park officials mentioned that hot weather could trigger a phenomenon called “Summer Branch Drop.” This is a seasonal occurrence where seemingly healthy trees can suddenly drop branches without warning.
This phenomenon is most common in the black oaks of Yosemite National Park, occurring frequently in the summer, especially on hot, calm afternoons with minimal wind.
In July 2025, a 29-year-old Chinese-American Google engineer named Angela Lin was hiking with friends at Tuolumne Grove in Yosemite National Park when a large sequoia branch broke off suddenly, striking her head and causing her death.
Angela’s boyfriend, David Hua, recalled the tragic incident, stating that as they were walking along a paved trail admiring the giant sequoias about a mile from the parking lot, they heard a loud crack from above. “Two to three seconds later, that branch came crashing down from the sky, a thick branch hitting Angela, followed by a pile of smaller branches falling behind me,” he told the media last year.
In their park announcement on Monday, Yosemite stated that branches prone to breaking are usually growing horizontally rather than vertically and tend to be longer, extending to the edge or beyond the canopy of the tree. While some fallen branches may show signs of decay or old injury, officials pointed out that many branches that fall during this season appear “quite intact.”
Older trees with weaker growth seem to be more prone to this issue, and trees that have previously dropped branches due to “Summer Branch Drop” are also more likely to experience a recurrence.
Visitors can take certain precautions to prevent such tragedies or injuries, such as avoiding having babies or elderly individuals directly under large oak trees.
During hot summer days, it is advised to avoid setting up tents or picnicking under the branches of black oaks. Officials warned, “If you hear a loud cracking sound above you, quickly move away from the trees.”
The park authorities emphasized that avoiding problematic trees not only helps mitigate this risk but also assists park personnel in taking timely action to maintain tree health.
Furthermore, the park urged the public to assist by promptly notifying park patrols if they witness any fallen trees or branches. It is currently unclear how many people have been injured or killed in the park due to this hidden hazard, and whether “Summer Branch Drop” caused the giant branch to break off last summer, resulting in Lin’s tragic death.
(Partial reference from New York Post reporting)