Orange County Fire Authority crews responded to the 29400 block of Silverado Canyon Road at about 10:15 p.m. Wednesday and attacked the blaze from the ground and air after the flames spread from a house fire.
Containment is at 30% as of Friday.
The ferocious winds that hampered efforts during the early morning hours Thursday died down at night, enabling firefighters to make progress, although hot spots were still flaring up on the Silverado Canyon hillsides.
The injured firefighters are now out of the hospital. One suffered a leg injury and the other had minor bruising.
The Bond Fire forced mandatory evacuations for residents in the Silverado Canyon and Williams Canyon areas as it continued to grow at a rapid rate of speed Wednesday night. Modjeska Canyon is also under mandatory evacuation orders, and residents in the area of Borrego Canyon and other nearby communities were also warned to prepare to evacuate.
BOND FIRE MAP: See areas under mandatory, voluntary evacuation orders
Residents of Foothill Ranch and Portola Hills west of El Toro and north of the 241 toll road were also placed under mandatory evacuation orders. Remaining parts of Portola Hills remained under voluntary evacuation warnings, officials said.
The Orange County Sheriff's Department says 25,000 residents are under mandatory evacuation.
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Fire officials urged those under evacuations to heed the orders. The Red Cross established a temporary evacuation center at Santiago Canyon College, Lot 2, located at 8045 E. Chapman Avenue.
Residents in the Lake Forest area are also under voluntary evacuation orders. The order applies to homes from the 241 toll road along Bake Parkway to Musick north to the Irvine border, and from the 241 north to Bake to Foothill Ranch Community Park.
However, OCFA later lifted evacuation orders for the Lake Forest area, north of Alton Parkway, east of the 241.
There is no confirmation about what caused the initial flames. However, rumors are flying among evacuees about the source.
"A lot of people have been getting generators because the power companies cut our power during the winds, so people have been getting generators out there, and there's a lot of people that probably have never had a generator before. It possibly was started from the generator into the brush," one resident said.
Residents who didn't evacuate were left without power and cell service.
A smoke advisory issued by the South Coast Air Quality Management District will be in effect Friday morning due to the wildfires burning in Orange and Riverside counties, with regulators saying air quality is being affected throughout northern and central Orange County and the Long Beach area.
The AQMD's advisory, in effect through Friday morning, warned that unhealthy Air Quality Index (AQI) levels were being recorded throughout northern Orange County and the Long Beach area due to the Airport Fire, burning near the Corona Municipal Airport, and that the Bond Fire was affecting air quality levels throughout central Orange County in cities such as Newport Beach, Irvine and Lake Forest, with AQI levels reaching the very unhealthy category in places.
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City News Service contributed to this report.