At least 13,000 acres burned by Pawnee Fire in Northern California

So far, there have been no reports of injuries or casualties. But 22 buildings have been destroyed, with 600 more threatened by flames. Mandatory evacuation orders are in place for some communities and about 1,500 people have been forced from their homes.

"I just got in this truck and left ... and left everything there. It changes directions, it burns real quick," Lake County resident Alan Phillips told CNN affiliate KTXL. "They say leave, leave."

Gov. Jerry Brown declared a state of emergency in parts of the region due to the blaze, which is now 17% contained.

More than 1,400 firefighters are battling the Pawnee Fire, assisted by more than 20 engines, two helicopters and a handful of air tankers, according to CNN affiliate KGO.

Hoping for the best, bracing for the worst

Several shelters are open to house evacuees, and there is at least one staging area for animals.

Residents of Spring Valley told CNN affiliate KOVR that it could be three to five days before they're allowed back in to their homes.

Those staying in shelters are hoping for the best, but bracing for the worst.

"You think, are we going to have a home when we go home?" evacuee Lola Claypool told KOVR. "Where are we going to go? What are we going to do? That's all we've got."

Still, some homeowners decided to take a chance and stay with their properties.

"I haven't thought anything about getting out of here," one Spring Valley homeowner told KTXL. "We got a Honda generator, and that's all we need, you know?"

But state fire officials warn that residents should get out while they can. "When you are asked to evacuate, that's what we ask you to do. It's for your own safety," Cal Fire Capt. Amy Head told KTXL, adding that wind patterns have made fighting the Pawnee fire difficult.

Grim memories of Santa Rosa

More than 200 personnel have been monitoring the fire from agencies such as the Lake County Sheriff's Office, the US Forest Service and the California Conservation Corps.

Flames were first reported early Saturday evening driven by "low relative humidity, erratic winds and above normal temperatures," according to Cal Fire.

The cause of the fire is under investigation.

Lake County is about 100 miles northwest of the capital, Sacramento.

The Pawnee Fire is bringing up grim memories of last year's fires in Santa Rosa, which is about an hour and a half from Lake County. Wildfires there ravaged more than 245,000 acres, destroyed nearly 7,000 structures and killed 42 people, making it one of the worst fires in California history.