Twin Northern California blazes fueled by dry vegetation and hot, windy weather grew Monday to become the largest wildfire in state history, becoming the norm as climate change makes the fire season longer and more severe.

The two fires burning a few miles apart and known as the Mendocino Complex are being treated as one incident. It has scorched 443 square miles (1,148.4 square kilometers), fire officials said Monday.

The fires, north of San Francisco, have burned 75 homes and is only 30 percent contained.

The size of the fires surpasses a blaze last December in Southern California that burned 440.5 square miles (1,140.8 kilometers). It killed two people, including a firefighter, and destroyed more than 1,000 buildings before being fully contained on Jan. 12.

Hotter weather attributed to climate change is drying out vegetation, creating more intense fires that spread quickly from rural areas to city subdivisions, climate and fire experts say. But they also blame cities and towns that are expanding housing into previously undeveloped areas.

More than 14,000 firefighters are battling over a dozen major blazes throughout California, state Department of Forestry and Fire Protection spokesman Scott McLean said.

“I can remember a couple of years ago when we saw 10 to 12,000 firefighters in the states of California, Oregon and Washington and never the 14,000 we see now,” he said.

Crews did make progress over the weekend against one of the two blazes in the Mendocino Complex with help from water-dropping aircraft, Cal Fire operations chief Charlie Blankenheim said in a video on Facebook.

But the other one is growing after spreading into the Mendocino National Forest.