Why protecting your home from wildfires requires protecting your community from wildfire
We’ve all read the news reports or seen the interviews of firefighters describing the unprecedented size
and intensity of wildfires the past few years. When a firefighter, with decades upon decades of wildfire
experience, uses terms like “fire behavior like I’ve never seen before in my career” and “historical,” it’s
time to stand up, take notice and more importantly, take action.
Call it what you will, global warming, climate change or atmospheric warming, present day California is hotter, drier and receiving less precipitation year over year. When you consider that Jan-March 2022
was the driest on record and the past two decades were the driest in the last 1200 years, the evidence seems unimpeachable. These hotter, drier conditions superimposed upon large-scale buildup of dead and dying vegetation, have aligned to create the perfect storm of extreme wildfire behavior. Based on
statistics from the National Interagency Fire Center, as of Aug. 2, 2022, more than 5.7 million acres have burned, already surpassing the 10-year average of 3.6 million acres. Yet, the peak of wildfire activity is still to come, with forecasted higher-than-normal fire potential, due to the historic drought conditions,
above-average temperatures and below-normal precipitation.
Home ignitions during a wildfire are due to one of three causes, direct flame contact, radiant heat or embers. When we think about wildfires, we often envision huge walls of flames engulfing homes. The
reality is that most homes do not ignite from direct contact with a flame front. In fact, it’s estimated that up to 90% of homes are destroyed indirectly by wind-borne embers that are carried ahead of the fire
perimeter. When the heat generated by an intense wildfire is combined with wind, small burning embers (aka firebrands) can travel several miles away from the fire perimeter.
Community wildfire protection has traditionally focused on the “From the wildlands in” approach. Using the combined methods of fire suppression and forest management, the goal of this approach is to keep
the wildfire front from entering the community. Fire suppression, while a very effective strategy in
preventing the fire front from encroaching on the community in its path, is outmatched in its efforts to prevent embers, which may travel several miles on the wind, from raining down upon the community.
Research first put forth by renowned fire scientist, Jack Cohen, and simulated in the laboratory by the Insurance Institute for Business and Home Safety (IBHS) shows that when these embers land on easily ignitable fuels (pine straw, leaves, dry vegetation, etc.) in proximity to a home, the possibility of ignition
is greatly increased. This is a prime goal of defensible space, creating a buffer between the home and ignitable vegetation by removing that fuel which embers can ignite. Embers may also penetrate and ignite the home through insufficient vents, windows compromised by heat or gaps in exterior cladding. Mitigating such vulnerabilities is the goal of Home Hardening Measures.
The majority of homes lost to wildfire are first ignited by embers and small flames. By reducing the susceptibility of the area immediately around the home and the home itself, the chances of a home
surviving an ember storm or small spot fire are greatly increased. Work in the Home Ignition Zone (HIZ)
is also called creating defensible space.
The Home Ignition Zone is an area 100-200 feet from the foundation and includes vegetation, the home itself, and other structures or attachments like decks, furniture, fences, and outbuildings. Home
hardening is a key component of the Home Ignition Zone.
The more homes in a neighborhood that are hardened, the less one home can be a threat to another
home. Additionally, embers that have entered and ignited a structure within the neighborhood become
an additional, dangerous source of embers for additional ignitions, putting the entire community at increased risk. For these reasons, a community approach to wildfire protection becomes imperative.
This approach to community wildfire protection, “From the home out,” is a hallmark of the Firewise USA® program. Successful community wildfire protection, however, requires a multi-pronged approach. Combining work from the home out to the community boundary by eliminating potential ignition sites for dangerous embers with the efforts of forest managers and the fire authority, “From the wildlands in” to keep the wildfire front from entering the community. It is this tandem approach that will greatly increase the survivability of both your home and your community, in the event of a wildfire.
Firewise Coordinator, Fire Safe Council for Monterey County