Officials may never know what started the Lilac fire

What sparked the Lilac fire earlier this month in north San Diego County may never be known.

Cal Fire San Diego Chief Tony Mecham said investigators know exactly where the Lilac fire began off the west side of Interstate 15 on Dec. 7, roughly a half-mile south of State Route 76.

“We’ve narrowed it down to a one-square-foot area where it started, but we didn’t find anything,” Mecham said. “There was nothing there that we could tie to a heat source.”

There were no electric lines in the area. There was no lightning, no evidence of an arson device or a cigarette butt or carbon from a vehicle’s exhaust, he said.

“Unless we get a tip through the public or some other type of follow up, we may never know,” the California Department of Forestry and Fire Protection official said.

Mecham said it’s possible that whoever started the fire has no idea he or she is responsible. For example, he said, a truck dragging a metal chain that was throwing off sparks could have started the blaze, which began during extremely high-risk fire weather, with humidity levels in the single digits and strong Santa Ana winds.

The Lilac fire burned 4,100 acres in Bonsall, destroyed 157 structures and damaged 64 others. It is still unclear exactly how many of those structures were homes as opposed to buildings such as greenhouses and barns.

Forty-six horses were killed or went missing at San Luis Rey Downs training facility.

“The fire is still under investigation,” Mecham said. “We’re not ruling anything out. It was something related to the freeway. What we’ll probably end up with is a designation of ‘undetermined.’”

jharry.jones@sduniontribune.com

Jones writes for the San Diego Union-Tribune