The list of possible causes is long.
“Our investigation might be over quickly for some of these fires — say, if we find a piece of metal nearby from a catalytic converter that back-fired,” the sheriff said. “But others might not be so easy to determine. We’ll be talking to people in the areas to see if they saw anything to see if arson might have had a role.”
Investigators will visit each burn site and go down a list, marking what they know and don’t know.
Is it near a road? That raises the possibility that the flames were ignited by a hot tailpipe, sparks from a catalytic converter or a discarded cigarette from a motorist. Is there a railroad nearby? Are there any power lines?
Investigators will also study the ground for footprints or tire tracks and analyze the burn pattern.
Two of the blazes broke out at military bases, where training exercises with gunfire have been known to spark flames.
A 2003 wildfire in Southern California that killed 15 people, destroyed more than 2,000 homes and blackened 300,000 acres in October and November was caused by a lost hunter who set a signal fire. Sparks from power lines were blamed for wildfires in the San Diego area in 2007 that left five people dead and burned down about 1,500 homes.
This time, the hardest-hit areas were in the cities of San Marcos, where a college campus shut down and canceled graduation ceremonies, and Carlsbad, where the Legoland amusement park was forced to close.
A dozen wildfires popping up in a single day is not unheard of in the drought-stricken state, but it’s a phenomenon usually seen during the dog days of summer.
“What makes the San Diego area fires so unique is that we had tinder-dry conditions and Santa Ana winds in the month of May, and that’s unprecedented,” state fire spokesman Daniel Berlant said.