There is often a false sense of security from property owners that the fire department will be able to extinguish all fires that start in and around their homes. Although all local fire agencies stand ready to quickly respond to contain any wildfires that may start, sometimes conditions make it impossible to protect every home. Ultimately, there is no guarantee that firefighters will be able to protect your home during a wildfire emergency. Therefore, it is your responsibility to prepare your home and private property before a fire threatens your area. The Ready! Set! Go! Program is designed to provide you with critical information on retrofitting your home with fire-resistant materials, creating defensible space around your home so there is a safe working environment for firefighters, and preparing you to safely evacuate well ahead of an emerging wildfire.
What is your risk?
An individual property’s wildfire risk is based on several factors. These include the likelihood of a fire starting in the area, the potential intensity of the fire, the exposure of the home, and the susceptibility of the fire spreading and causing damage to the infrastructure on the property.
The US Department of Agriculture recently created the online Wildfire Risk to Communities webpage. You can explore this interactive website with maps, charts, and resources to help better understand and reduce wildfire risk.
The following sections are devoted to helping homeowners understand their own risk to wildfires and providing methods to prepare for future wildfires through proper planning, building, and maintenance of their properties.
How Homes Ignite
Wildfires spread by a combination of a moving flaming “front”, and embers which are carried through the air by smoke and wind.
Buildings ignite during wildfires because of either embers, radiant heat, or direct flame contact.
Embers are light enough that they can be blown through the air and can result in fire spread through spotting. Spotting is where embers start additional smaller fires downwind from the main fire. Should these embers land on or near your house, they could ignite dry vegetation and other combustible material, or could enter your home through openings such as vents.
As seen in the above “Ember Storm Test Video”, near-home ignitions will subject some portion of your house to either a direct flame contact exposure, where the flame contacts the home, or radiant heat exposure. If the fire is close enough to a combustible material, or the radiant heat is high enough, an ignition will occur. Even if the radiant exposure is not large enough or long enough to result in ignition, it can preheat surfaces making them more vulnerable to ignition from direct flame exposure. With any one of these exposures, if no one is available to extinguish the fire and adequate fuel is available, the initial small spot fire will grow into a large one. Homes do not spontaneously ignite during a wildfire event. They are lost because of the growth of initially small fires, either in or around the home or building.
The most catastrophic fires in Santa Barbara County, such as the 1990 Paint Fire, the 2008 Tea Fire, and the 2009 Jesusita Fire, had hundreds of homes lost because the wildfire became an urban fire. During these situations, the ember production of the burning homes themselves cause home-to-home fire spread which is exponentially more dangerous and much harder to control than a wildland fire.