Firefighters were battling 13 wildfires in California on Sunday, including the one around the northern towns of Middletown and Cobb, where hundreds of structures were destroyed.

Fire officials said the fire through Middletown and Cobb, dubbed Valley Fire, in northern California on the U.S. west coast, was among the most destructive as it spread rapidly and chased thousands of residents from their homes in and around those communities.

California governor Jerry Brown declared a state of emergency in areas hit by the blaze.

Reports reaching here said the Valley Fire has consumed more than 40,000 acres since erupting Saturday afternoon in rural Lake County, while another fire, known as Butte Fire, was partly contained.

Daniel Berlant, public information officer for the California department of forestry and fire protection, or Cal Fire, was quoted as saying that "this (Valley Fire) is one of those fires that has been so fast moving."

Four firefighters were hospitalized with second-degree burns after they were dropped off by helicopter to battle the fire, north of San Francisco.

Hot weather and drought conditions apparently worsened the situation.

On Friday, some 3,500 more people were evacuated from another blaze, dubbed the Rough Fire, which is burning in Kings Canyon National Park in central California.