Donald Trump has declared the wildfires tearing through homes and forests in California a “major disaster” and has released federal aid to help put them out.

More than 14,000 firefighters are battling 585 fires that have ravaged about a million acres of land – an area roughly one-fifth the size of Wales.

California Governor Gavin Newsom said in a statement that the declaration will also help people in counties affected by the fires with crisis counselling, housing and other social services.

The fires continued to rage on Saturday. Good weather throughout the day helped firefighters but smoky skies grounded water-dropping aircraft for some of the day, setting back their efforts.

The storms predicted for Sunday were expected to aid those efforts by changing the direction of the wind.

Evacuation orders were lifted in some areas on Saturday but state and local officials warned residents in other threatened areas to prepare to flee at any moment.

“There’s not a feeling of pure optimism, but a feeling of resolve, a feeling of we have resources backing us up,” Sonoma County Supervisor James Gore said.

The fire burning in California’s wine country, north of the San Francisco Bay, had only 1,400 firefighters assigned to battle the blaze.

By comparison, the state had 5,000 firefighters assigned to the Mendocino Complex in 2018, the largest in the state’s history.

“All of our resources remain stretched to capacity that we have not seen in recent history,” said Shana Jones, the chief for CalFire’s Sonoma-Lake-Napa unit.

Underscoring the danger the fires pose for firefighters, the Sonoma County sheriff’s office released dramatic video of the helicopter rescue Friday night of two firefighters trapped on a ridge line at Point Reyes National Seashore.

They were hoisted to safety as flames advanced.

The wildfires were first set off by more than 12,000 lightning strikes. About two dozen major fires are attracting most of the state’s resources.

Some fires doubled in size within 24 hours, fire officials said.

Most of the damage was caused by three clusters of fire “complexes” that were ravaging forest and rural areas in and around the San Francisco Bay Area in northern California.

Among the casualties were ancient redwood trees at California’s oldest state park, Big Basin Redwoods, plus the park’s headquarters and campgrounds.

Smoke from the fires made the region’s air quality dangerous, forcing people to stay inside.

Overall, the fires have killed six people, destroyed nearly 700 homes and other structures and forced tens of thousands from their houses.

“Tuesday night when I went to bed I had a beautiful home on a beautiful ranch,” said 81-year-old Hank Hanson of Vacaville. “By Wednesday night, I have nothing but a bunch of ashes.”

Tens of thousands of homes were threatened by flames which spread through dense and bone-dry trees and brush.

Five deaths involved fires burning in wine country north of San Francisco, while the other death was a helicopter pilot who crashed while dropping water on a blaze in Fresno County.

Henry Wofford, the spokesman for the Napa County Sheriff’s Office, said three of the bodies were found Thursday in a burnt home.

The area was under an evacuation order due to “very, very heavy” fire that he said burnt multiple homes.

In neighbouring Solano County, Sheriff Thomas Ferrara reported the death of a man, and the other victim was a Pacific Gas and Electric utility worker who was found dead on Wednesday in a vehicle in the Vacaville area.

At least 14,000 people in Solano County remained under mandatory evacuation on Friday, Solano County Undersheriff Brad DeWall said. He said 119 homes have been destroyed in his county.

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

In Napa County, Crosswalk Community Church has transformed its sanctuary and gymnasium into an evacuation shelter, filling the floor with cots spaced at least six feet apart.

Pastor Peter Shaw said the church has seen a steady stream of people stopping for resources. Some were just looking for information, while others needed gift cards for food and basic needs.

“Covid-19 complicates everything,” Mr Shaw said in an email. “Socially distanced cots drastically decreases our capacity.”

A few people have stayed the night, he said, adding several people parked their RVs in the church parking lot.

“The longer the evacuations stay in place, I suspect the more people we will see,” he said.