Governor Gavin Newsom said in a news conference that California had “reached out across the border” into Canada for resources and support, abc.net.au reported.

“Many of you will recall, I think it was 2017, the support that we provided and the support that we provided in turn of some of the best wildfire firefighters from Australia,” Newsom said.

“We also have requests out for that talent, as well.”

The Federal Government said no formal request for Australian assistance had been made yet through the Department of Foreign Affairs and Trade or firefighting agencies.

More than 12,000 firefighters aided by helicopters and air tankers are already battling bushfires throughout California.

Two firefighters dressed in yellow suits spray a hose on a charred tree.

Three groups of fires, called complexes, burning north, east and south of San Francisco have together scorched 2,020 square kilometers, destroyed more than 500 structures and killed at least six people.

The blazes, coming during a heatwave that has seen temperatures top 38 degrees, have taxed the state’s firefighting capacity but assistance from throughout the country has begun to arrive, with 10 other US states sending fire crews, engines and aircraft to help, Newsom said.

“We have more people but it’s not enough. We have more air support but it’s still not enough and that’s why we need support from our federal partners,” he said.

A traffic jam on a highway as a blaze rips up one side of the road.

The state has been hit by its worst dry-lightning storms in nearly two decades as close to 12,000 strikes have sent flames racing through lands left parched by the heatwave.

Some 175,000 people have been told to leave their homes.

Video footage posted on social media showed giant Redwood trees, some more than 2,000 years old, standing largely unscathed among the torched ruins of buildings in and around Big Basin Redwoods State Park.

A complex of blazes east of Palo Alto and another in country south of Sacramento are the seventh and 10th-largest wildfires in state history, respectively, according to the California Department of Forestry and Fire Protection (CalFire).

The agency warned that more dry-lightning storms were expected as early as Sunday (local time).

“We’re still understaffed for a fire of this size,” said Daniel Potter, a CalFire spokesman, in reference to the Santa Cruz blaze where crews are working 72-hour shifts to save homes in towns such as Ben Lomond.

Plumes of smoke and ash fouled air quality for hundreds of kilometers around fire zones, adding to the misery and health risks of residents forced to flee or those stuck inside sweltering homes that lacked air conditioning.

Medical experts warned that the coronavirus pandemic has considerably heightened the health hazards posed by smoky air and extreme heat, especially for older adults and those already suffering from respiratory illnesses.