Officially, "the cause is still under investigation" a spokesman for the U.S. Forest Service said.
The Rim Fire has destroyed 111 structures, including 11 homes, and poses a threat to ancient giant sequoias.
The fire is 35% contained, officials said Friday.
It's so large it can be spotted from space.
Fire officials are estimating full containment on the blaze by Sept. 20.
Smoke from the Rim Fire is affecting air quality thousands of miles away from the source.
A stunning time-lapse from Yosemite captured the fire’s rapid growth from August 22–27, 2013.
Jon Passantino is a deputy news director for BuzzFeed News and is based in Los Angeles.
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