ALTURAS, Calif. » Firefighters in Northern California were battling several lightning-sparked wildfires Friday, including a blaze in rural Modoc County that forced about 120 people to evacuate.

The fire near the community of Day had burned through nearly 18 square miles of brush and heavy timber and was threatening 150 structures Friday, two days after it began. It was only 10 percent contained.

Officials were expected to send additional fire crews to supplement the 700 or so firefighters battling the blaze, which is burning in steep terrain and could be aggravated by winds and lightning from more expected thunderstorms, said state fire spokesman Dennis Mathisen.

"It’s a challenging firefight due to the extreme fire conditions we’re experiencing," Mathisen said.

California is in its third year of drought, which has heightened the fire danger. The California Governor’s Office of Emergency Services announced Friday that it has asked the state’s National Guard to activate specially trained helicopter units to help fire agencies.

"The forward deployment of these will help incident commanders and the personnel they are directing save lives, homes and personal property as well as valuable watershed by providing critical resources within a moment’s notice," California emergency services Director Mark Ghilarducci said in a statement.

The fire in Modoc was among more than 40 that have broken out as a result of lightning strikes since Wednesday. Most were in remote areas and were not threatening homes, and many of them were quickly contained.

In Washington state, a new wildfire burning intensely amid high winds forced the evacuation of about 200 homes Friday.

Officials ordered the evacuations and closed part of state Highway 20 because of the surging fire that started in north-central Washington halfway between Twisp and Winthrop.

The Sun Mountain Lodge, a luxury resort near Winthrop, was also evacuated as a precaution.

Janet Pearce, a spokeswoman for the state Department of Natural Resources, said some structures had burned. It wasn’t known if they were homes or other buildings.

Back in California, fire crews also were battling a blaze in Sierra National Forest about 60 miles northeast of Fresno that threatened dozens of homes and forced a handful of evacuations Friday afternoon.

Evacuations were ordered for some 50 houses in Arnold Meadows, but many are vacation homes and only about a dozen people had to evacuate when deputies went door-to-door, The Madera County Sheriff’s Department said.

The blaze was burning close to the Mammoth Pool Reservoir, a popular recreation spot that supplies drinking water, and crews were trying to finish containment lines on the section near the reservoir, said fire spokesman Matthew Chambers.

The blaze had burned through nearly 13 square miles and was 15 percent contained.

In Yosemite National Park, residents from about 50 homes returned Friday afternoon. They were the last remaining evacuees from a fire that had burned through 7 square miles and destroyed a home and a duplex. It was 78 percent contained.

The park remained open and was largely unaffected.

The causes of the Yosemite and Sierra fires were not known.