LOS ANGELES (REUTERS) - Firefighters waging an all-out "mini-Alamo" defence of the Mount Wilson Observatory saved the famed astronomical complex from a blaze raging through rugged peaks above the foothill suburbs of Los Angeles, a US Forest Service spokesman said on Wednesday (Sept 16).
The pitched battle to protect the mountaintop observatory and an adjacent communications site came as power equipment belonging to electric utility Southern California Edison came under scrutiny in an investigation into the cause of the so-called Bobcat Fire.
The western flank of the fire crept to within just 152m of the observatory on Tuesday as 12 ground crews fought with hand tools and bulldozers to fend off the flames while a squadron of water-dropping helicopters and airplane tankers loaded with fire retardant doused the blaze from the air, officials said.
By Tuesday night, helped by calming winds, firefighters managed to keep the flames at bay.
In addition to the 116-year-old observatory, crews saved a nearby cluster of broadcast and communications towers critical to the greater Los Angeles area, Forest Service spokesman John Clearwater said.
"It came down to an almost mini-Alamo," Mr Clearwater told Reuters by phone, referring to the pivotal siege in the Texas revolution against Mexico in 1836. "Those firefighters were determined to defend that mountaintop down to the last drop of water."
The 1,740m summit in the San Gabriel Mountains is home to about 50 buildings in all connected with the array of radio antennae and the adjacent observatory, which conducted pioneering astronomical research for much of the 20th century.
No buildings were burned, Mr Clearwater said.
The observatory was likewise narrowly spared from a much larger blaze fought off by fire crews in 2009.
CAUSE UNDER INVESTIGATION
Since erupting on Sept 6, the fire has charred some 17,800ha of the Angeles National Forest, belching smoke and ash over much of the greater Los Angeles area for over a week and forcing evacuations of several communities at the foot of the mountains.
The blaze was one of dozens of wildfires that broke out during the Labour Day holiday weekend, stoked by a late-summer heat wave that baked much of the US West Coast before cooler weather prevailed.
The cause of the Bobcat fire was under investigation.
On Tuesday, Southern California Edison notified state regulators that one of its high-voltage substations experienced a tripped circuit just minutes after smoke from the blaze was first observed near a large dam and reservoir.
The "electric safety incident" report by the company, a unit of Edison International, also said Forest Service personnel had asked the utility to remove a specific section of one of Edison's overhead power lines in the vicinity of the dam.
The Forest Service "has not alleged that SCE facilities were involved in the ignition of the Bobcat Fire," the utility said.
The company added that it was submitting its report "in an abundance of caution" given the agency's "interest in retaining SCE facilities in connection with its investigation."
A SoCalEdison spokesman, Mr David Song, said the company was"cooperating fully" with the probe.
While no structures have been lost from the Bobcat Fire, threats from the blaze remain significant, with containment lines established around just 3 per cent of its perimeter, Mr Clearwater said.
More than 11,000 personnel remain assigned to fighting the fire, which the Forest Service expects could intensify in the days ahead, he said.