 -- Two massive wildfires raged out of control in California, destroying buildings, forcing the evacuation of thousands of people, and injuring four firefighters.

The Valley fire in Lake County, about 100 miles north of San Francisco, grew to 62.5 square miles (40,000 acres) Sunday morning, according to the California Department of Forestry and Fire Protection. The four firefighters injured battling the blaze suffered second-degree burns and were hospitalized in stable condition.

California Gov. Jerry Brown declared a state of emergency in Lake and Napa Counties, which would expedite funding and resources to battle the blazes.

Two towns and people living along a stretch of State Route 29 were forced to evacuate.

Mike Lopez, the president of CAL FIRE, talked to Good Morning America on Sunday and was asked whether exhaustion was a factor amid a long exhausting season for firefighters. “Since the drought is in its fifth year,” he said, CAL FIRE has been on the front lines literally 10 months out of the year, and now we’re heading into a September burn season when the fuels are completely dry. The Santa Ana winds will start taking off in Southern California here real soon. We’ll be at it all the way in December unless we get some significant rain.”

About 60 miles southeast of Sacramento, the Butte fire roared through brush in the foothills, having burned more than 101 square miles (65,000 acres) and forced 2,700 people out of their homes since it ignited Wednesday.

More than 3,850 firefighters were battling that blaze, which was 20 percent contained.

It had destroyed 86 homes, 51 other buildings, and was threatening about 6,400 more.

The Associated Press contributed to this report.