A wind-driven brush fire that erupted in Silverado Canyon late Wednesday night has burned thousands of acres, injured two firefighters and forced about 25,000 people in Orange County to flee their homes Thursday.

The incident, dubbed the Bond Fire, began about 10:15 p.m. as a “fully engulfed house fire” in the 29000 block of Silverado Canyon Drive, said O.C. Fire Authority Chief Brian Fennessy.

Erratic, gusty winds pushed the fire into nearby brush, quickly spreading the blaze into the hills.

“It came so fast. We barely, barely could get out,” resident Susan Iwamoto said.

A number of homes were destroyed as the blaze exploded, but it’s unclear exactly how many as the damage is still being assessed, Fennessy said.

As of 8 p.m., the fire had scorched 6,400 acres and was 10% contained, according to the Fire Authority.

It was earlier listed at 7,200 acres but was downgraded due to more accurate mapping, officials said.

About 500 firefighters from more than 30 agencies have been called to the area to battle the blaze.

“We’re feeling pretty good about the effort that they put in,” O.C. Fire Capt. Thanh Nguyen told KTLA. “We had seven helicopters that went at it hard today, dropping water. We had bulldozers, hand crews, and we had engine companies, and they put in a solid amount of work.”

Two firefighters were taken to a hospital after being injured while battling the blaze, officials said. Video shows one of the firefighters being airlifted from the scene.

“My understanding is that they were treated on scene, transported to a local hospital,” Fennessy said in an afternoon news briefing. “Their exact condition is unknown to me.”

The fire chief added that he was impressed with the swift response from agencies statewide that allowed crews to stop the blaze from moving further into difficult-to-defend areas, including Modjeska and Silverado canyons.

Fennessy said he believed all homes had been saved in Modjeska Canyon.

As of Thursday afternoon, the main communities impacted were Foothill Ranch, Portola Hills, Modesjka Canyon, Silverado Canyon, Lemon Heights and Cowan Heights. The flames were spreading mostly south-southeast, though shifting winds could change that, said O.C. Sheriff Don Barnes.

Thursday night’s gusts were not as strong as the night before. But firefighters were concerned about the winds possibly shifting directions, back toward the Cleveland National Forest.

“We’ve seen wind kick up without any warning whatsoever, so that’s one thing that we’re keeping an eye on,” Nguyen said.

Officials have not yet determined the cause of the house fire on Silverado Canyon Drive.

The area was under a red flag warning for gusty winds and dry conditions when the fire erupted Wednesday night.

Smoke from the Bond Fire, along with the nearby Airport Fire in Corona, clouded the air and triggered a smoke advisory in place through Friday. A wide swath of the region was expected to be impacted, including most of Orange County; central, south and east Los Angeles County; the Corona and Norco areas of Riverside County; and the southwest San Bernardino Valley.

Evacuation orders, road closures

Mandatory evacuations have been ordered for Silverado Canyon, Modjeska Canyon, Williams Canyon, Foothill Ranch and Portola Hills west of El Toro and north of the 241 toll road.

The rest of Portola Hills was under a voluntary evacuation order.

Updated evacuation orders can be found on the Orange County Sheriff’s Department website.

Santiago Canyon Road was closed between the Highway 241 toll road and Jackson Ranch Road, as well as eastbound from Orange.

After earlier being shut down in both directions, the toll road highways 133, 261 and 241 were later reopened.

Fennessy urged residents to be aware of their surroundings and evacuate if they feel worried.

“Even if you don’t see smoke, you don’t hear sirens, but you have a concern that maybe the fire’s a little too close — that’s enough,” he said. “That’s enough to have your belongings prepared and evacuate. You don’t have to wait for us to call.”

About 60 deputies were assigned to coordinate evacuations, control traffic and provide security in evacuated areas, Barnes said.

Fennessy said evacuees would not be able to return soon due to downed power poles and wires.

“We’re not just going to let people into those communities as long as there’s other hazards out there,” he said.

Evacuees were encouraged to seek safety with family, friends or in a hotel. “Due to COVID-19, no congregate shelter is offered,” the Fire Authority stated.

However, a Red Cross temporary evacuation points was set up in Orange at El Modena High School, 3920 E. Spring St.

Small animals could be taken to the O.C. Animal Care shelter in Tustin, at 1630 Victory Road.

Two shelters were open for large animals: the Anaheim Equestrian Center at 1370 S. Sanderson Ave. in Anaheim, and the O.C. Fair & Event Center at 88 Fair Drive in Costa Mesa.

The Los Alamitos racetrack was at full capacity and not being used for evacuations.

Those who need assistance with animals can call O.C. Animal Care at 714-935-6848.

Residents can sign up to get public safety alerts at AlertOC.com or get more information by calling the hotline at 714-628-7085.