About 8,000 firefighters have been deployed across the state, said the California National Guard, which has been called into action.
"California's severe drought and extreme weather have turned much of the state into a tinderbox," California Governor Edmund Brown said in a statement yesterday.
"Our courageous firefighters are on the front lines and we'll do everything we can to help them."
The dead firefighter was named as Dave Ruhl, 38, from South Dakota, who was killed on Thursday while fighting the Frog Fire in the Modoc National Forest outside Alturas.
Wildfires are a fact of life in much of California, but they have been exacerbated by bone-dry conditions as the western US state is gripped by a fourth year of record drought.