A wildfire along northern California’s inland coastal range has burned about 47,000 acres and forced the closure of two highways, officials said Sunday, while a blaze near the Oregon border also expanded after killing a firefighter.

The Rocky Fire in Lake County north of San Francisco had grown by about 20,000 acres since Saturday, according to Cal Fire, a state Web site for fire information.

“This is a very fast-moving wildfire,” Cal Fire spokesman Daniel Berlant said Sunday. “With[in] a five-hour period last night, 20,000 acres burned, and that is unprecedented growth in that short amount of time.”

The fire has closed parts of Highways 20 and 16, has destroyed 24 homes and 26 other outbuildings and threatens 6,301 structures, according to Cal Fire.

Nearly 2,000 firefighters are battling the fire, which broke out Wednesday and is only 5 percent contained, the same percentage as on Saturday, according to the Web site. About 12,000 people have been evacuated or are under evacuation advisories.

Drought-stricken brush and grasslands have made parts of California vulnerable to wildfires, and dozens are burning throughout the state.

Among numerous fires is the Frog Fire, which officials said killed a firefighter on Thursday. David Ruhl, 38, a married father of two from Rapid City, S.D., died while assigned to the fire in the Modoc National Forest near California’s border with Oregon.

Ruhl was alone and working as incident commander on the fire, said Forest Service spokesman Ken Sandusky. It is common for a leader on a fire to travel alone, Sandusky said, but he declined to release more details on Ruhl’s death.

The Frog Fire, which was about 4 percent contained, grew to 3,900 acres and erratic winds have pushed it in all directions, according to the U.S. Forest Service’s InciWeb online fire information center.

A red-flag warning, designating the threat of gusty winds that risk fanning flames, was expected to remain in effect until late Sunday in the area of the Frog Fire. InciWeb said the flames are not expected to be fully under control until Aug. 12.

— Reuters