David Ruhl, an engine captain from South Dakota's Black Hills National Forest, died sometime Thursday while battling the fire in the Modoc National Forest, U.S. Forest Service officials said in a press release.
The blaze, burning about 100 miles south of the Oregon border, is one of 18 fires raging across the state. Most are in Northern California.
Forest Service officials didn't say how Ruhl died. He had vanished sometime Thursday and his body wasn't recovered until Friday morning.
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Gov. Jerry Brown, who declared a state of emergency for California on Friday because of the fires, expressed his condolences.
"Firefighter Ruhl will be remembered for his service and bravery and we extend our deepest condolences to his family, friends and colleagues with the U.S. Forest Service," Brown said in a statement.
Ruhl had been in California since June working with state and Forest Service firefighters.
The fire in the Modoc National Forest started Thursday afternoon and rapidly grew to cover 800 acres.