Some of the dozens of wildfires sweeping across California more than doubled in size in just one day — killing at least five and leaving tens of thousands fleeing from their homes.

“Everything is gone,” distraught resident Nick Pike told CapRadio after he and three neighbors lost their homes in Vacaville, a town about 55 miles northeast of San Francisco that had to be evacuated.

The fires were sparked in part by a record-breaking heatwave and an estimated 11,000 lightning strikes recorded over the last week, mostly in northern and central California, with some doubling in size over 24 hours Thursday, officials said.

They have killed at least five so far, officials told the Associated Press, including three civilians who died in Napa County and one in neighboring Solano County.

It wasn’t immediately clear whether the listed fatalities included a Pacific Gas & Electric utility worker who was found dead in Vacaville on Wednesday while on duty helping clear electrical hazards for first responders.

Earlier the same day, the pilot of a firefighting helicopter was killed in a crash during a water-dropping mission in Fresno County.

At least two other people were missing and more than 30 civilians and firefighters have been injured, authorities said.

More than 10,000 firefighters were on the front lines, including thousands arriving from neighboring regions, with National Guard troops also staffing hand crews and flying helicopters. Some C-130 military aircraft also had been outfitted as air tankers.

“It’s still not enough,” Cal Fire Assistant Chief Billy See said. “We’re still drastically short for a fire of this size.”

Officials were also alarmed that untrained locals appeared to be trying to band together to create volunteer brigades and fight the fires themselves.

“The dangers out there to their own lives outweigh anything they can accomplish,” Cal Fire spokesman Dan Olson said.

“They’re putting their lives in jeopardy.”

The fires have destroyed at least 175 buildings, including homes, and threatened tens of thousands more.

As the fires continued to intensify, residents were warned to prepare their most important items for evacuation, including in Santa Cruz, a central coast city of 65,000.

“Prepare early so that you are ready to go at a moment’s notice,” Mayor Justin Cummings told residents.

With Post wires