Grants Pass, Ore. ? The nation’s largest active wildfire grew to 308,000 acres Friday, threatening to become the biggest fire in Oregon history.

The blaze, in the Siskiyou National Forest and adjoining lands in southwestern Oregon and Northern California, was close to surpassing a 1933 wildfire that burned 311,000 acres in northwest Oregon.

The sun rises over the fire base camp setup along the Chetco River road near Brookings, Ore. Fire continued to threaten the community of Agness in the Rogue River Canyon and an area near the small coastal town of Brookings on Friday, as the nation's largest active wildfire grew to 308,000 acres.

The wildfire had at one point threatened about 17,000 people in several small towns in the Illinois Valley. That danger has eased, but the fire continued to threaten the community of Agness in the Rogue River Canyon and an area near the small coastal town of Brookings.

Sheriff’s deputies Friday were asking some Brookings-area residents to prepare to leave their homes immediately if notified.

More than 5,000 people are fighting the fire. More than $27 million has been spent trying to extinguish it, but it was only 15 percent contained.

After touring the wildfire Thursday, U.S. Forest Service Dale Bosworth said thinning national forests and restoring the natural role of fire in the ecosystem should be made a top priority.

“The most important thing we can do in a good part of the West is doing some thinning and reintroduce fire back into these fire-dependent ecosystems in a controlled manner,” Bosworth said.

The National Fire Information Center reports 5 million acres have burned in the country this year, including more than 715,000 acres in Oregon. Bosworth said that the fires have cost $325 million to fight.