By Adrees Latif

AETNA SPRINGS, Calif. (Reuters) – California braced for more lightning storms, which have sparked over 600 wildfires in the past week, but firefighters got some relief as temperatures eased off record highs.

The worst of the blazes, including the second and third largest in California history, burned in the San Francisco Bay Area with roughly 240,000 people under evacuation orders or warnings across the state.

Much of Northern California, including the Sierra Nevada Mountains and coast, was under a “red flag” alert for dry lightning and high winds, but the National Weather Service dropped its warning for the Bay Area.

Close to 300 lightning strikes sparked 10 new fires overnight and more “sleeper fires” were likely burning undiscovered in areas shrouded by dense smoke, Governor Gavin Newsom said.

One huge blaze burned in ancient coastal redwood forests south of San Francisco that have never seen fire due to usually high relative humidity levels, Newsom said.

“We are in a different climate and we are dealing with different climate conditions that are precipitating fires the likes of which we have not seen in modern recorded history,” Newsom told a news briefing.

The wildfires, ignited by over 13,000 lightning strikes from dry thunderstorms across Northern and Central California since Aug. 15, have killed at least seven people and destroyed over 1,200 homes and other structures.

Smoke from wildfires that have burned over 1.2 million acres (485,620 hectares), an area more than three times larger than Los Angeles, has created unhealthy conditions for much of Northern California and drifted as far as Kansas.

The LNU Complex, the second largest wildfire in state history, began as a string of smaller fires in wine country southwest of Sacramento but has merged into a single blaze that has burned around 350,000 acres of Napa, Sonoma, Lake, Yolo and Solano counties.

It was 22% contained as of Monday while to the south the SCU Lightning Complex was nearly as large, at 347,000 acres, and only 10% contained.

“I’m nervous, I don’t want to leave my house, but lives are more important,” Penny Furusho told CBS television affiliate KPIX5 after she was told to evacuate from the south flank of the SCU fire.

Over 14,000 firefighters are on the wildfires, with 91 fire crews traveling from seven states and National Guard troops arriving from four states, Newsom said.

(Reporting by Adrees Latif in Aetna Springs, California; Editing by Tom Brown)