Wildfires threaten thousands in Northern California

(CNN) -- Wildfires raced across Northern California overnight, charring at least 9,000 acres and forcing thousands from their homes, fire officials said.

The King Fire is roaring through the El Dorado National Forest, about 60 miles east of Sacramento

Some 8,600 acres have burned and the flames are only 5% contained, according Cal Fire.

Thousands of folks have had to evacuate.

"We still have about 500 homes -- we're calling them threatened -- and we just people to stay out of them for now," Lynne Tomalchoff, a Cal Fire spokeswoman, told CNN affiliate KCRA.

Mandatory and voluntary evacuations are in place across large swaths of El Dorado County.

About 250 miles to the north and near the Oregon border, the Boles Fire is much smaller at 400 acres, but more threatening.

Some 1,500 homes are under evacuation orders in Siskiyou County. The evacuations cover the communities of Weed and Carrick.

"We're encouraging those folks to leave their homes," Suzi Brady with Cal Fire told affiliate KDRV. "This is not the year you want to stay there. The fuel types are extremely dry."

More than 100 structures have been damaged or destroyed, according to Allison Giannini with the Siskiyou County Sheriff's Department.