Firefighters face rough terrain as they battle Mt. Wilson blaze

Firefighters were still battling a 50-acre wildfire that is threatening the historic Mt. Wilson Observatory and a collection of vital communications towers in the San Gabriel Mountains.

The fire was 25% contained as of 8:20 a.m. Wednesday, said Angeles National Forest spokeswoman Seneca Smith. The increase in size, from 30 acres Tuesday, was not due to the fire growing but a more accurate estimate Wednesday morning, she said.

“It could be several days before we see full containment,” Smith said. The fire is burning on terrain that is “very steep and rocky and inacessible by foot,” making it difficult for firefighters to establish a containment line in those areas.

About 200 firefighters were on the scene Wednesday morning, she said.

More than two dozen antenna towers cluster on the peak of Mt. Wilson. Smith estimates that hundreds of millions of dollars’ worth of communications equipment could be at risk, including federal and county facilities used for emergency communications, commercial television facilities and radio transmitters. Damage to the communications towers could disrupt cellphone, television and radio reception, as well as communications for emergency responders.

The observatory is a Los Angeles County landmark — home to two of the first large modern telescopes — and has been at the forefront of crucial discoveries about the expansion of the universe, said USC physics, astronomy and math professor Nicholas Warner. Universities including USC also use the solar observatory for physics research today, he said.

Mt. Wilson remained closed Wednesday after authorities evacuated the observatory Tuesday, but about four employees remained — mostly maintenance and facilities workers — to help firefighters with access, Smith said. Officials have closed Mt. Wilson Road, the only roadway in and out of the mountaintop complex.

Reach Sonali Kohli at Sonali.Kohli@latimes.com or on Twitter @Sonali_Kohli.

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