In the weeks after 86 people were killed and over 14,000 homes and businesses were destroyed in the Camp Fire at Paradise, California three influential individuals and organizations urged the consideration of banning or restricting development in areas that are at high risk from wildfires.
First there was the Los Angeles Times Editorial Board on November 24 writing that “To rebuild Paradise as it was, would be land-use malpractice.” The Board continued, “The question facing state and local authorities is whether Paradise — and other towns that have burned — can be rebuilt to withstand the next, inevitable wildfire. If not, how does California relocate communities and restrict new construction while respecting property rights and not worsening the state’s affordable housing crisis? At a minimum, cities should remap fire-prone areas and focus reconstruction in areas with lower risk. “
Then on December 10 the group 1000 Friends of Oregon released “A New Vision for Wildfire Planning” that recommended avoiding development in high risk areas.
Five days before he retired on December 15 Ken Pimlott, Director of the California Department of Forestry and Fire Protection, was quoted by the Associated Press as saying officials should consider banning home construction in areas vulnerable to wildfires.
Cities, counties, and planning boards (where they exist) are often under pressure to approve new housing developments. They want to expand their tax base. Developers try to fit as many homes into a new subdivision as possible to maximize their investment. This too often results in homes that are 20-feet apart. If one is ignited by a burning ember that may have traveled a quarter of a mile from a fire (or a burning home) the radiant heat alone can ignite the homes on both sides. Then you can have a self-powered conflagration spreading house to house through a city. As long as the structures are that close together, the homeowners have not reduced the fuel in the Home Ignition Zone within 100 feet of the structure, and the home itself is not built to FireWise standards, a massive disaster can be the result.
The NFPA and the FireWise program recommend reducing flammable material within 100 feet of structures, and spacing trees at least 18 feet apart that are within 30 feet of the home. At the 60 to 100-foot distance tree canopies should be at least 6 feet apart. Another house that is 15 to 50 feet away is also fuel and if it ignites will be a serious threat.
If a homeowner wants, or is required, to reduce the flammable material within 100 feet of their residence, what are they expected to do if there is another home 20 feet away that is really a large assembly of flammable material?
Some of the homes in Paradise, California that burned were less than 20 feet apart. According to measurements using Google Earth, the structures in the photo at the top of this article were 14 to 18 feet from each other.
The National Institute of Standards and Technology released a report on the Waldo Canyon Fire that burned 344 homes and killed two people in Colorado Springs, Colorado in June, 2012. They concluded that current concepts of defensible space did not account for hazards of burning primary structures, hazards presented by embers, and the hazards outside of the home ignition zone. In addition, NIST recommended:
High-density structure-to-structure spacing in a community should be identified and considered in [Wildland Urban Interface] fire response plans. In the Waldo Canyon fire, the majority of homes destroyed were ignited by fire and embers coming from other nearby residences already on fire. Based on this observation, the researchers concluded that structure spatial arrangements in a community must be a major consideration when planning for WUI fires.
After studying the Carr Fire that destroyed 1,079 residences at Redding, California earlier this year, retired CAL FIRE Battalion Chief Royal Burnett reached similar conclusions.
It was easy to figure out why the houses on the rim burned — they were looking right down the barrel of a blowtorch. Even though they had fire resistant construction, many had loaded their patios with flammable lawn furniture, tiki bars and flammable ornamental plants. Palm trees became flaming pillars, shredded bark became the fuse, junipers became napalm bombs. Under current standards houses are build 6 to an acre; 10 feet to the property line and only 20 feet between houses. Once one house ignited, radiant heat could easily torch the next one.
We have to learn to live with fire
Reducing the chances that a fire in a populated area will turn into a disaster that burns thousands of homes involves at least three categories of factors, in addition to weather:
- Envelope of the structure itself: characteristics of the roof, vents, siding, doors, windows, foundation, fences, eaves, and decks. A FEMA publication (13 MB) has excellent detailed recommendations. Headwaters Economics found that the cost of building a fire-resistant home is about the same as a standard home.
- Home Ignition Zone, as described above — topography and fuel within 100 feet.
- Community infrastructure and planning: distance to nearby structures, evacuation capability, safety zones, road and driveway width, turnarounds at the end of roads, signage, and emergency water supply. Again, the FEMA document has great recommendations.
Someone asked me recently what needs to be done to keep from repeating disasters like we have seen within the last year at Paradise, Redding, and the Napa Valley. I told him that there is no one thing that needs to be done, such as raking or “forest management”, it requires a comprehensive holistic approach.
The items we have listed here only apply within communities. There is of course much that can be done surrounding the places where people live that would reduce the vegetation or fuel and decrease the intensity and ember generation potential of a fire as it approaches an urban area. Large scale fuel management including fuel breaks and prescribed fire programs are usually conducted by state and federal agencies.
The weakest link in the chain principle applies here. If one of these categories is sub-par, the individual structures and the entire community in a fire-prone environment is at risk. And if a homeowner does not do their part, it can endanger their neighbors.
The warming climate is demonstrating that wildfires are becoming increasingly perilous. It is unlikely that local governments or states are going to ban development in fire-prone environments, but it is their responsibility to protect their citizens by enacting sensible standards.
