Angeles National Forest fire explodes to almost 5,000 acres, sends ash far and wide

An out-of-control brush fire kept growing Monday morning in Angeles National Forest north of Azusa, sending ash into communities miles away and forcing the evacuation of the Mt. Wilson Observatory.

The Bobcat fire started shortly after noon Sunday near Cogswell Dam and had burned an estimated 4,871 acres of brush and timber by Monday morning, U.S. Forest Service officials said. It was 0% contained.

Staff members at the Mt. Wilson Observatory were ordered to evacuate Monday morning as the fire raged toward the grounds, according to an online post. The observatory posted dramatic video of the approaching fire Sunday night before evacuations were ordered. Dramatic time-lapse video showed the approaching fire.

The fire also threatens to destroy a seismic station housed at Mount Wilson that is operated by Caltech and has recorded major earthquakes for 100 years, according to seismologist Lucy Jones.

Angeles Crest Highway is closed from 10.6 miles east of La Canada Flintridge to Islip Saddle due to the wildfire, according to Caltrans.

Ash from the blaze rained down along the 210 Freeway corridor and has prompted the South Coast Air Quality Management District to issue a smoke advisory for the foothill communities and into the Santa Clarita Valley through Monday, warning of unhealthy air for sensitive people.

About 100 firefighters with five engines, three hand crews and two water tenders fought the fire from the ground while four helicopters and five fixed-wing aircraft launched an aerial assault, according to fire officials.

The wind is expected to blow out of the west and southwest Monday from 10 to 15 mph, said Mike Wofford, a meteorologist with the National Weather Service in Oxnard.

By Tuesday morning, conditions will change as hot, dry winds are expected to blow out of the north, which could push the blaze toward populated areas in foothill communities. Winds Tuesday are expected at 15 to 25 mph with wind gusts up to 50 mph near ridge tops, Wofford said. Those Santa Ana winds will bring single-digit humidity, he said.

Seneca Smith, public information officer for Angeles National Forest, said fire crews faced very difficult conditions Monday afternoon, battling hot, dry weather and rugged terrain. Most of the firefighters who initially responded to the blaze on Sunday are still working, so fatigue is a factor, she said.

By early Monday afternoon, the fire’s southern perimeter was about 4 miles from the San Gabriel foothill areas of Monrovia, Arcadia, Bradbury and Duarte. With Santa Ana winds expected Tuesday, fire officials are focused on halting the southward movement of the fire, Smith said.

“We are extremely concerned about the communities to the south,� she said. “They are our No. 1 priority, along with Mt. Wilson and the Chantry Flat community.�

Fire officials were meeting with local law enforcement agencies Monday afternoon to determine where evacuation notices may be announced, Smith said.

The U.S. Forest Service announced it would temporarily close national forests and campgrounds across California beginning at 5 p.m. Monday due to extreme heat and dangerous fire conditions. Closing those recreation areas — including the Angeles, San Bernardino, Los Padres, Cleveland, Stanislaus, Sierra, Sequoia and Inyo national forests — will help reduce the potential for human-caused fires, officials said.

“Existing fires are displaying extreme fire behavior, new fire starts are likely, weather conditions are worsening, and we simply do not have enough resources to fully fight and contain every fire,� said Randy Moore, regional forester for the Forest Service Pacific Southwest Region.

Additionally, the temperature — which reached at least 103 on Sunday afternoon where the Bobcat fire is burning — was not expected to dip low enough overnight to be helpful to firefighters, and the humidity will remain low, meaning grass and brush will be dry and ready to burn.

A temporary flight restriction is in place over the fire area, and drones are prohibited.

Throughout Southern California, firefighters were hampered by a record-breaking heat wave that swept across the state this Labor Day weekend and brought triple-digit temperatures to many areas.

Across the county in Sunland-Tujunga, 62 firefighters from the city and county departments put out a brush fire Sunday at Hansen Dam in the San Fernando Valley in 43 minutes. The blaze grew to only five acres.