In their Saturday morning update, California National Forest stated that Holy Fire had grown to a staggering 21,473 acres and was 29 percent contained.
The blaze is affecting two of the state’s counties – Orange and Riverside.
The spread of the blaze and threat to properties as well as air quality concerns has led California’s Governor Jerry Brown to declare a state of emergency for both counties.
Mandatory evacuation notices are in place for Mayhew/Sycamore Creek, Glen Eden, Horsethief, Rice Canyon, Rice Lake, McVicker, Machado and South El Cariso and Riverside.
There are also voluntary evacuations in Shoreline zones.
According to government incident website InciWeb: “The evacuation area covers 7,449 single family homes and numerous commercial structures with estimated evacuees totalling 21,484 people.”
The Holy Jim community has lost 12 structures in the blaze so far following a structural assessment.
There are several forces at work in attempting to control the blaze: The US Forest Service, CAL Fire, Riverside County Fire, Orange County Fire Authority, and the California Highway patrol.
A total of 1,511 personnel are tackling the fire, which is being fuelled by short grass and brush dried out by hot temperatures.
One method of attack on the fire is the use of firefighting planes and helicopters.
Aircraft have been repeated flights, dropping water and bright pink retardant to protect Lake Elsinore and other foothill communities as the fire spreads through the thick, bone-dry brush of the Cleveland National Forest.
“The air operations have been relentless,” public information officer Thanh Nguyen told the Union-Tribune.
“When we drop so many gallons of water, we’re doing it to overwhelm the heat with the coolness of the water.”
Weather conditions are adding to the chaos caused by the fire with hot temperatures and strong winds fanning the flames.
Current forecasts see temperatures of between 91-97 degrees Fahrenheit (32-36C) and westerly wind gusts of up to 25mph.
These hot and windy conditions can create extreme fire behaviour, as well as increasing dangers for those tackling the blaze.
Firefighters are working on strengthening containment barriers in order to prevent spreading to residences.
In their latest update 7am, local time (3pm BST) the Cleveland National Forest tweeted: “#Holyfire New Fire numbers this morning: 21,473 acres with 29% containment!”
In total there are 13 fires burning across California, with more than 13,500 firefighters tackling the blazes.
More than 671 acres have been scorched and more than 2,000 buildings damaged or destroyed.