What are the top causes of fires in Sonoma Valley?

It’s not only arson, homeless encampments or even lightning strikes that worry firefighters: it’s the unintentional ignition of a grass fire by a landowner trying to clear his property.

“With the exception of illegal burning, electric utilities and lightning, the top preventable causes of wildfire would be mowing or other equipment use,” said Fire Marshall Trevor Smith, of the Sonoma Valley Fire District.

According to Cal Fire, approximately 95% of all wildfires in California are caused by human activity, nearly always unintentional.

Such activity includes grinding, welding, vegetation cutting and other machine-based field work that in some cases, ironically, is intended to reduce fuel in the water-depleted landscapes of California. Weed Abatement Ordinances in effect across Sonoma County “require applicable property owners to keep weeds and grasses cut down and maintained through the duration of fire season,” explained a press release from the Sonoma Valley Fire District issued Oct. 6.

“As part of this requirement, it is critical that property owners, contractors and retailers are aware of the proper mechanical equipment recommended for safe weed abatement and how to properly use that equipment in order to prevent fires.”

The report said, “Local fire departments across the County have responded to numerous fires that were preventable. In many cases, improper equipment was used to cut dry grasses and open fields.” Lawn mowers, for instance, are built for residential lawns, not tall grasses or piles of leaves – the metal blade of a mower can strike a rock, creating a spark and igniting a fire.

Tow chains dragging behind vehicles are another top cause of wildfire, particularly along roadways. Even brakes worn too thin can create sparks from moving cars or trucks, and driving into dry grass or brush is inherently risky. “Hot exhaust pipes and mufflers can start fires that you won’t even see — until it’s too late,” warns Cal Fire.

Fire officials recommend that weed abatement and mowing of seasonal grasses occur before 10 a.m. and should be avoided altogether during excessively dry, hot and windy days. Efforts should be made to ensure the appropriate equipment is being used, which may mean renting or buying a walk-behind weed eater, high weed mower or weed eater that is designed for use on dry seasonal grasses.

Other advice from the Fire Marshall includes:

•Remove rocks in the area before you begin operating any equipment – a rock hidden in grass or weeds is enough to spark a fire when struck by a metal blade;

•Ensure spark arresters are in place on all portable gasoline-powered equipment including tractors, chain saws, weed eaters, mowers, brush cutters, etc.

•Keep the exhaust system, spark arresters, and mower in proper working order and free of carbon buildup;

•Keep the engine free of oil and dust and keep the mower free of flammable materials;

•Have a round-point shovel, a phone to call 9-1-1, a back-pump water-type fire extinguisher, or water supply ready to use.

For additional information, review the “One Less Spark – One Less Wildfire” campaign on Cal Fire’s website, ReadyForWildfire.org.