San Francisco, Oct 12 (IANS): The toll from massive wildfires raging across California has increased to 23 with over 600 reported missing, police said.

Sonoma county, one of the worst-hit areas, has alone reported of 285 missing persons, reports CNN.

"I'm optimistic that we will get a lot of people connected," Sonoma county Sheriff Rob Giordano said on Wednesday night.

"At the same time we have to be realistic and start searching for the ones we found are missing."

Of the 23 people victims, 13 were killed in the Tubbs wildfire in Sonoma, officials said.

According to Cal Fire, Tubbs fire, one of 22 blazes burning in the state, is the the fifth-deadliest fire in recorded California history.

Firefighters battling 22 blazes were challenged on Wednesday by blustery conditions and shifting winds.

Gusts had died down earlier this week, but on Wednesday they blew between 20 and 40 mph and conditions were still extremely dry, with low humidity and no rain. Thursday's forecast is for similar conditions.

More than 20,000 people were ordered to evacuate as of Wednesday, and authorities were encouraging others to pack "ready-to-go bags" with documents and medicines in case they had to flee the fast-spreading flames on a moment's notice.

The wildfires that started on Sunday night have burned nearly 170,000 acres throughout the state, CNN reported.

The largest fires were in Northern California's Sonoma, Napa and Mendocino counties, filling the picturesque landscape of the state's wine country with charred rubble and clouds of smoke.

According to state officials, almost 8,000 firefighters are currently involved in trying to contain the blazes.

The equipment being used includes 550 fire trucks, 73 helicopters and over 30 planes.