Two young campers were killed in Yosemite National Park Friday when a limb from an oak tree fell and struck their tent, according to the National Park Service.
The limb fell from a tree at the Upper Pines Campground in Yosemite Valley at about 5 a.m. (8 a.m. ET), according to a Yosemite National Park statement.
Park rangers responded to the site to provide medical assistance but found that the campers had already died after the limb fell on their tent while they were sleeping, the statement said.
"Our thoughts are with the families as they grieve this tragedy," park superintendent Don Neubacher said in the statement.
Yosemite National Park did not identify the two campers but said they were both minors.
The park service did not say why the tree limb fell. California is in the fourth year of a historic drought, leading to parched conditions in large parts of the state.
Last month in Pasadena, a 75-foot tree fell and injured eight children at a summer day camp, NBC Los Angeles reported.
In 2013, a falling tree at a camp near Yosemite killed a camp counselor in 2013, according to NBC Bay Area.