A car overheats on northbound Interstate 5 as it crests the Newhall Pass, slowed by traffic.

It pulls to the side of the road near the Calgrove Boulevard off-ramp.

The engine ignites and wind blows sparks into nearby brush. Within moments, smoke is billowing from the side of hill next to the freeway, and flames are climbing toward power lines and homes.

It’s a common scenario to Los Angeles County Fire Department responders.

Fires in the Santa Clarita Valley are frequently started on the sides of one of the area’s two major thoroughfares, either by burning cars or by burning brakes on big rigs, fire officials say.

Other frequent causes of Santa Clarita Valley wildfires are lightning strikes and burning cigarettes tossed out of car windows.

Causes vary
It’s either environmental conditions or human activity that cause fires, said county fire Assistant Chief Bill Niccum.
Summer thunderstorms — like those the National Weather Service warned of Saturday and today in the Santa Clarita Valley — can mean a chance of “dry lightning” strikes that can ignite wildfires.

Besides car fires, tossed flaming cigarettes and burning truck brakes, man-made fires are sometimes caused by power tools being used during high-fire-danger conditions.

Arson fires — those deliberately set by humans — make up a small percentage of local wildfires, Niccum said.

Eliminating brush
Many Santa Clarita Valley fires erupt on the sides of Highway 14 or Interstate 5.

A 32-acre brush fire in Agua Dulce earlier this month was caused by a vehicle that caught fire and ran into a fence near Highway 14.

Commercial vehicles that travel the two throughways are often the problem.

“A lot of times, their brakes overheat,” Niccum said. “That overheated material flies off and goes into the grass, which starts our fires.”

Niccum said the Interstate 5 corridor near the Calgrove Boulevard exit a likely place for fires because cars overheat going up the hill or burn their brakes going down the canyon stretch.

Across Los Angeles County, firefighters responded to a total of 2,250 vehicle fires in 2008. But the number declined to 1,858 such incidents in 2010, according to county statistics.

County fire officials work with the California Department of Transportation to clear brush along freeways in a bid to reduce car and brake fires.

“We do address that, but it’s impossible to do it all,” Niccum said.

Caltrans spokeswoman Judy Gish said brush clearance stretching to 200 feet along freeways is part of the agency’s regular maintenance efforts.

“We cooperate with them as much as possible,” she said.

The agency also sprays vegetation along freeways to kill weeds so that they don’t need to be cleared, Gish said.

Battling fires
As unpredictable as fires can be, county fire officials use information and advocacy to best prepare themselves against fires.

At 9:45 a.m. every day, all fire chiefs take part in an operations conference, sharing resources available that day — whether it’s engines, helicopters and camp crews, Niccum said.

“How we manage those resources is based on our weather,” he said.

Using analysis and projections, county fire officials are able to figure out where the day’s hotspots are likely to be, he said.

Staying prepared
County fire officials also engage the community in preventing fires and containing them as quickly as possible.

For instance, the county launched the “Ready! Set! Go!” program in 2009, which encourages property owners to prepare themselves against fires and to come up with a plan in case they are evacuated because of fire, he said.

Public education becomes key in a hazardous fire area like the Santa Clarita Valley, especially during high-fire-danger “Red Flag” days.

Red Flag days become common in the late summer and fall when high winds paired with high temperatures and low humidity create an increased threat of rapidly spreading fires.

Public education is provided through city councils, town councils, neighborhood watch meetings and other opportunities for Fire Department officials to talk to the public, said spokeswoman Stephanie English.