The Bobcat Fire that burned more than 115,796-acres threatened the Mt. Wilson Observatory and forced thousands to evacuate, the utility giant reported Monday, may have been sparked by tree branches reaching a Southern California Edison overhead conductor.
In a letter to the California Public Utilities Commission, SCE announced that it had recognized the possibility.
Investigators from the U.S. Forest Service did not share the specifics of the inquiry with SCE, but the organization told regulators, "SCE understands that in addition to retaining SCE's overhead conductor, USFS also removed and retained three tree branches in the area."
"SCE is investigating the cause of the ignition and the 12:16 p.m. relay on its system, and evaluating whether vegetation in the area could have been a factor, including whether vegetation may have encroached within the minimum clearance distance or contacted the section of the overhead conductor retained by USFS."
It's not the first big wildfire that SCE facilities might have begun. SCE admitted that it could be liable for the deadly Woolsey Fire after officials from the Ventura County Fire Department concluded that SCE equipment caused the blaze.
Firefighters who, since Sept. 6, have been fighting the Bobcat Fire do not expect full containment until Oct. 30. 171 buildings, including 87 residences, were destroyed by the Bobcat Fire and 47 buildings, including 28 residences, were damaged. According to Los Angeles County parks officials, the Nature Center at the Devil's Punchbowl Natural Area was demolished.
The fire at 12:21 p.m. was recorded near Cogswell Dam in the Angeles National Forest. On Sept. 6, and at 12:16 p.m., SCE reported, a portion of SCE's Jarvis 12 kV circuit in the area experienced a relay operation. At Mount Wilson, a camera captured smoke in the region as early as 12:10 p.m.
On September 16, SCE removed the conductor's 23-foot-long line for the U.S. Forest Service to be included in their inquiry.
"SCE personnel were permitted into the subject area and removed an approximately 23-foot section of 1/0 ACSR conductor (south phase) that was situated between an H-Frame structure comprised of Pole Nos. 4786005E and 4786004E, which had been significantly damaged in the fire and was no longer erect, and another H-Frame structure comprised of Pole Nos. 2127468E and 1583439E," SCE said in the letter.
The containment of the fire reached 92 percent on Sunday, as the 115,796-acre blaze that has been burning for over a month continued to work with more than 300 firefighters.
At lacounty.gov/recovery/damage-inspection, a map, collected from continuous field damage inspection and subject to change, can be viewed.
With the exception of Big Santa Anita Rd (The Chantry Road), all evacuation orders have been canceled and most roads have been reopened.
Over the weekend, temperatures cooled steadily, but increased to the 90s and low humidity on Monday, increasing the danger of burning.
It has not been determined the cost of fighting the fire.