California wildfires: 14,000 firefighters battling 18 major outbreaks in state's worst blaze

Twin fires, treated as one incident north of San Francisco, become the state’s biggest ever wildfire

At least 14,000 firefighters, with volunteers that include prison inmates, are battling 18 major fires that are burning across thousands of square miles throughout California.

On 6 August, twin fires being treated as one incident, north of San Francisco became the largest wildfire in state history, destroying 443 sq miles (1,148 sq km) – an area nearly the size of Los Angeles.

The size of the fire, known as the Mendocino Complex fire, has surpassed that of last year’s Thomas fire, which burned 281,893 acres in Santa Barbara and Ventura counties when it destroyed more than 1,000 structures.

Evacuations have been ordered across California and the rapid spread of the blazes is showing no sign of slowing, with gusty winds threatening to fan the flames even further.

Firefighters will tackle the fires directly with water and retardant where they can. And when they can’t take that direct approach, they will retreat to a ridge, wide road or stream where they use bulldozers to cut a “fire line.”

There they’ll wait for the blaze to come to them while lighting “backfires” to clear vegetation between the fire line and the approaching blaze.

Experts say whichever approach Cal Fire takes, California firefighters are often more aggressive in trying to extinguish wildfires than those in other less-populated states. That’s because California wildfires are increasingly threatening sprawling urban areas.

“Cal Fire is really an urban firefighter service in the woods,” said Arizona State University life sciences professor Stephen Pyne, a wildfire management expert.

Cal Fire spokesman Scott McLean said firefighters use both approaches to battle the large blazes, including the growing twin fires about 100 miles (160km) north of San Francisco.

Mr McLean said firefighters are using the direct approach to prevent the fires from reaching urban areas along Clear Lake while retreating in national forests “and letting the fire come to us.”

Experts have said it’s impossible to surround a fire that large, especially with 17 other major fires requiring attention in the state.

“We are building lines. Picking and choosing where we think we can take a stand,” Mr McLean said. “Attacking it where we can and waiting and letting it come to us when appropriate.”

Experts say the best way to fight these destructive wildfires is to prevent them in the first place when building homes and other buildings.

“It’s the embers, not the fire itself, that destroy most homes,” said Steve Conboy, a construction expert whose company develops fire-resistant chemicals to apply to wood.

Agencies contributed to this report