When the Eaton Fire flared up Jan. 9, flames producing heavy dark smoke climbed to the summit of Mount Wilson, a peak high above the San Gabriel Valley that is home to vital communication towers for the Los Angeles vicinity and the historic Mount Wilson Observatory.

What happened next is a fire protection success story.

Winds were light in the area, but the steep slopes were covered in heavy brush, providing fuel for a fire that started two days earlier in a Santa Ana windstorm described by firefighters as among the worst they've seen. Roads to the summit are twisting and narrow, making the area difficult to access for fire trucks and crews.

Flames could be seen near the towers and other structures at the summit with thick smoke drifting over the ridge.

On a day when five wildfires, including the deadly Eaton and Palisades fire, were burning in Los Angeles County, it was an unsettling sight.

"It was a wall of fire coming up the mountain," said engineering Dennis Doty, who was staffing the NBCLA transmission site.

He spoke with NBCLA during live coverage Jan. 9 as the flames advanced.

"It's going to be a long fight today, tonight and into tomorrow, but we're set up to weather this quite well," Doty said in the on-air interview.

His outlook was grounded in tried-and-true fire protection preparation.

"We do a lot of brush clearance here," Doty said. "That's part of our plan with NBCUniversal, so I had the defensible space that I needed. The building is concrete and steel. So, we're safer here than trying to get off the mountain, getting in a wreck with a fire truck."

Video from NewsChopper4 also showed a red line of fire retardant in heavy brush below the ridge.

Without vegetation for fuel close to the tower, the fire moved on. The communications equipment and Observatory were not damaged.

The Observatory, which was founded by George Ellery Hale in 1904, became the world's foremost astronomical research facility with what was the largest telescope in the world.

"It's very satisfying because I did my job right," Doty said. "If the site was defensible, I've done my job."

The peak remains without power one week after the fire. Fuel is trucked in daily to power generators.

"Without it, we're dead," said Scripps Broadcasting's Marty Shostrom. "No TV, no radio, no two-way, no emergency services. Nothing."

In September 2020, the 41,700-acre Bobcat Fire burned to within 500 feet of the Observatory. Closed for the pandemic at the time, staff members were evacuated. Backfires were set to rid the area of dry vegetation, providing a defensible space for firefighters to protect the peak.

The Eaton Fire near the foothill community of Altadena destroyed homes and businesses after it started on the night of Jan. 7.