Lightning strikes have sparked dozens of wildfires in northern California’s wine country, burning dozens of structures and forcing thousands to flee their homes.

California was hit by nearly 11,000 lightning strikes in 72 hours, sparking 367 fires, nearly two dozen of them major, as the state suffered a record heat wave, authorities say.

A group of fires covering more than 18,600 hectares near the city of Vacaville, south-west of Sacramento, raced through hills and mountains destroying 50 homes and other structures.

“This is my cousin’s home in Vacaville that just burned to the ground,” tweeted podcast show host Robert Hanna with a picture of a house in flames.

Diane Bustos told KPIX-TV that she and her husband were trying to escape when their vehicle caught on fire and they had to flee on foot.

“I got all these flames on me and I lost my shoe, but I made it. God saved me,” she said.

The blazes follow devastating fires across northern California in 2017 that killed 44, wiped out numerous wineries and destroyed nearly 9000 homes and other structures.

“In the last 72 hours we’ve experienced an historic lightning siege,” said California Department of Forestry and Fire Protection spokeswoman Lynnette Round on Wednesday.

Burned out vehicles after the fire has passed through Vacaville. Photo: Getty

So-called red-flag high winds are fanning fires caused by rain-less dry-lightning storms, sending flames racing through scrub and woodland parched by record-breaking heat and low humidity.

Another group of fires called the SCU Lightning Complex about 30km east of Palo Alto more than doubled in size overnight and is burning more than 34,400 hectares.

Governor Gavin Newsom has declared an emergency and requested 375 fire engines from out of state, with Arizona, Nevada and Texas sending assistance.

-with AAP