UPDATE: Aug. 17, 2015 at 7:19 p.m.
The size of the Cuesta Fire grew rapidly on Monday. CAL FIRE said Monday night that 500 acres had been scorched since the series of small fires along Highway 101 were first ingited on Sunday night.
Containment fell Monday from ten to five percent, but weather conditions were turning favorable again headed into the evening hours, according to Bennet Milloy, CAL FIRE PIO.
CAL FIRE issued an Evacuation Order for residents in Santa Margarita south of Highway 58 between Wilhelmina and Estrada. An Evacuation Center is being opened at Santa Rosa Academic Academy—you may remember it as Santa Rosa Elementary School—in Atascadero.
An estimated 500 people are affected, but CAL FIRE cautioned that number is a rough estimate based on the number of homes in the evacuation area.
Residents can call 2-1-1 for additional information.
CAL FIRE issued an evacuation order Monday afternoon related to the fires burning near Highway 101 east of the Cuesta Grade.
Santa Margarita residents living south of the railroad tracks are affected and can go to a shelter that was being set up at La Paloma Park in Atascadero.
The fire more than doubled in size Monday, expanding to some 300 acres. Containment was reduced to just five percent.
The investigation so far indicates a single vehicle caused a string of fires Sunday night, spanning from the Cuesta Grade to Highway 41 in eastern San Luis Obispo County.
CAL FIRE Engineer Bennet Milloy said the sparks could have been caused a couple of different ways.
"The three fires were likely started by the same vehicle," Milloy said. "Whether it was a chain or hot embers out of a catalytic converter hasn't been determined yet."
Cuesta's steep uphill grade indicates it likely wasn't from a vehicle's brakes, where sparks are generated when the pads wear out.
Investigators received several differing reports Sunday describing the vehicle in this case. An investigation is underway to locate the owner.
"In the State of California, even if you cause a fire accidentally, you would be responsible for that fire," Milloy said.
He also said at this point investigators have been following up on leads and have yet to access any video from traffic cameras.