Author(s): Lucian Deaton. Published on September 3, 2014.

IN MAY, A WILDFIRE IGNITED near the Rancho Bernardo Community in the City of San Diego, California. Over the next few days, 14 fires fueled by high winds and desperately dry conditions burned 26,000 acres, claimed 65 structures—46 of them homes—and caused $29.8 million in damages. The fires also claimed one life and forced 121,000 residents to evacuate.

The “May 2014 San Diego County Wildfires After Action Report,” compiled by San Diego County, noted that the wildfires were the largest in the region since the devastating fires of 2007 due to their timing early in the year and the number of fires burning simultaneously. As the media currently highlight the looming price tag of suppression costs in wildland fire, as national legislation is proposed for additional cost shifting for federal suppression response, and as the influencers that both buoy and balloon that cost are debated in research, I learned a simple and straightforward lesson from talking with a fire chief who saw the wildfires set their course: defensible space works.

Dave Hanneman, the fire chief in Chula Vista, California, explained to me that the fires ran the canyons, igniting dry vegetation as they were pushed quickly by high winds. While homes were lost, a vastly larger number were saved, he said, both by response activities and firefighters who were able to direct their efforts on the fire front as they watched the fire lay down when it reached properties where the fuels had been thinned and flammable debris removed. Chief Hanneman, who also serves as the president of the San Diego Fire Chiefs Association, noted that engaging structure fires involves many department resources and well over $1,000 an hour in operations costs alone.

The concept of defensible space is important in wildfire. Based on research into how homes ignite due to the effects of radiant heat, NFPA explains that defensible space espouses limiting the amount of flammable vegetation and materials surrounding the home and increasing the moisture content of remaining vegetation. NFPA calls this the “home ignition zone” and provides beneficial recommendations on actions residents can take to meet the risk around their home and property. When discussing this with residents, we often remind them that within 100 feet of their home is often another home. The importance of neighbors talking to neighbors about their communal risk and individual responsibilities is the foundation of NFPA’s Firewise Communities/USA recognition program, and more than 1,000 communities across the country have achieved recognition for working on those goals.

The term “defensible space” is not without debate, however, a result of the possible connotations it may convey. (“Survivable space” is often used as a synonymous term.) It has been pointed out that the word “defensible” implies that someone will come and defend it. Others argue that promoting “defensible space” will lull residents into ignoring local evacuation notices—or worse, prompt them to embrace a fatalistic response to wildfire’s destructive inevitably if they do not adopt, and pay for, every defensible space recommendation. In the San Diego fires in May, numerous resources from the City and County of San Diego, CALFire, the U.S. Department of Defense, volunteer fire departments, and law enforcement were engaged in the response. Yet, we know that even with such a robust response, resources cannot be placed in every driveway.

Fire can still impact homes that employ every step of mitigation, but adopting defensible space recommendations bore proof on the ground this past May. Amidst the ongoing national debate on suppression costs, I learned we need to do a better job capturing those firsthand accounts to support residents in their ongoing preparedness efforts, no matter where they are along the path of defensible space adoption.