After growing explosively to become California’s largest wildfire so far in 2022, a blaze in the foothills of the Sierra Nevada moderated on Sunday, with firefighters able to defend communities a dozen miles from Yosemite National Park.

The Oak fire, which was ignited and spread swiftly on Friday, has burned a total of 16,800 acres and still could threaten 3,300 homes and businesses. As of Monday morning, seven structures had been destroyed — an earlier estimate had said there were 10 — and more than 3,000 residents had been ordered to evacuate.

Cal Fire, the state’s main firefighting agency, said in a statement Sunday night that firefighters had made “good headway” against the blaze and that protective clearing by fire crews was shielding the small communities of Lushmeadows and Mariposa Pines.

“The fire continued to be active, but yesterday afternoon it did slow and moderate,” Capt. Jon Heggie, a battalion chief at Cal Fire, said by phone on Monday morning. “But the potential for it to grow still exists, and we will continue to fight this fire aggressively.”

Among those who mobilized to help evacuees and others affected by the fire was a group that the Mariposa Sheriff’s office identified as a private local militia.

“The public should be aware that the militia has not been activated or requested to act for any purpose by the Sheriff’s Office or any agency working the Oak Fire,” the sheriff’s office said in a Facebook posting.

The fire closed a highway leading to Yosemite, which is still recovering from the Washburn fire. That blaze started earlier this month and at one point threatened the park’s Mariposa Grove of sequoias, some of the world’s oldest trees. The Washburn fire is now all but extinguished.

As California fell deeper into a second year of drought in the spring, officials warned of a potentially catastrophic 2022 fire season across the state’s desiccated landscape. But so far this year, the state has managed to avoid the type of megafire that it has experienced in years past.

Last year at this time, the state was battling the Dixie fire, which burned nearly a million acres — more than 60 times the area of the Oak fire — and crested the Sierra to burn down the eastern slopes of the mountain range, a relatively rare occurrence.

The Oak fire is by far the largest wildfire in the state so far this year, besting the Washburn fire, which burned 4,900 acres, according to a tally by Cal Fire.

However, July is still early in the state’s traditional fire season, which runs through the summer and well into autumn, when the threat rises of more potentially lethal wind-driven wildfires.

California forests have always burned during the dry months. But a combination of rising temperatures from climate change and an abundance of ignitable vegetation — including tens of millions of trees that were killed during a previous drought a decade ago — have made the state’s forests particularly vulnerable to fire. Sixty percent of the state’s land area is classified by the federal government as being in extreme drought.