"We are making good progress on the fire", CalFire Deputy Chief Bret Gouvea told reporters at a mostly upbeat news briefing in Redding.
Australia's expertise was sought by USA authorities because of our familiarity with bushfires; in the U.S. media such fires are referred to as "wildfires".
Aided for a third straight day by diminished winds, ground crews extended buffer lines carved out of thick, dry brush along the fire's edge to 35 percent of its perimeter, with partial containment lines continuing even farther, officials said.
Officials are lifting more evacuations across Shasta County as firefighters gain containment on a wildfire burning in the region.
There are 4,271 firefighters battling the blaze, as well as 369 fire engines, 69 fire crews, 17 helicopters, 125 bulldozers and 84 water trucks.
Flames from a wildfire advance down a hillside near the Springs of Life Church in Casitas Springs, California. The Carr Fire burning in Shasta County has grown over 115,000 acres and is 35 percent contained.
The fire has burned an area four times the size of San Francisco.More news: TRUMP DIPLOMACY: The President Says He's 'WILLING TO MEET' Iranian Leaders
Approximately 90 large fires are now being fought in 14 states and nearly 400,000 hectares of ground has been lost.
With more than 20 active fires small and very large tearing across the state, California Gov.
Only approximately 3800 state prison inmates in California meet the minimum-custody and low-risk requirements for the firefighting assignment. Neither fire is reported to have injured anyone.
Cal Fire said that "steep terrain, erratic winds, and previously unburned fuels are contributing to spot fire potential".
"We're fighting nature with the amount of material we're putting in the environment, and that material traps heat, and the heat fosters fires, and the fires keep burning", he said.
Cal Fire did not report that any structures were damaged, though Highway 49 at China Hill Road remained closed to nonresidents.
"We're going to have more fire, more destructive fire, [and] more billions that will have to be spent on it", Governor Brown said. "We're being surprised. Every year is teaching the fire authorities new lessons".