Wildfire & Sprawl

How Residential Sprawl into High Risk Areas Increases Wildfire Jeopardizing Public Safety

Allowing residential development to sprawl into areas at high risk for wildfire increases the likelihood that lives will be lost and more fires will occur.  While building codes, defensible space, and other measures may reduce the risk, there is growing evidence that more is needed.  As a result, some local governments are discouraging the construction of new homes in wildfire high risk area especially where evacuation routes and fire suppression capabilities are limited. 

If you’re concerned about proposed development in an area at high risk for wildfire, then contact CEDS at 410-654-3021 or Help@ceds.org.  We can assist you in ensuring that the development does not put your family and your neighbors at greater risk.

What areas are at high risk for wildfire?

The wildfire risk is highest at the wildland–urban interface or WUI.  The Wikipedia WUI definition reads:

“In the United States of America, the wildland-urban interface (WUI) has two definitions. The US Forest Service defines the wildland-urban interface qualitatively as a place where “humans and their development meet or intermix with wildland fuel.”  Communities that are within 0.5 miles (0.80 km) of the zone are included.”

A number of factors are considered in the models used to develop wildfire risk or hazard potential maps:

  • Density of fuels (trees, shrubs, grass, etc.),
  • Slope,
  • Water sources,
  • Proximity to fire departments,
  • Extent of defensible space around structures,
  • Presence of powerlines,
  • Roofing-siding material combustibility, and
  • Number and characteristics of evacuation routes.

A U.S. Wildfire Hazard Potential map can be viewed at: https://usfs.maps.arcgis.com/home/item.html?id=fc7f208f4bf34cf3ad34eff72261b140

A number of states and local government GIS sites provide more detailed wildfire risk mapping.

What is Sprawl & Smart Growth?

The Greenbelt Alliance defines sprawl as:

“…the outward expansion of low-density residential and commercial development into the outer edges of cities and towns, far from downtown areas. ” 

The far superior alternative to sprawl is Smart Growth where new development is guided into or adjacent to areas with existing homes, businesses, etc.   Infill is a form of Smart Growth where development occurs on those small, vacant areas present in many towns and cities.  And the redevelopment form of Smart Growth replaces deterioated buildings with new structures.

Wildfire Risk Is Increasing

As shown in the following U.S. Forest Service map, wildfire risk is greatest in the western states but is also significant in the southeast.

The following National Interagency Fire Center table shows that the acreage of lands burned each year has increased considerably since the 1980s.

A 2017 study predicted a considerable future increase in the area burned by wildfire each year.  The increase is attributable in part to climate change.

More people living in high risk areas means more wildfires

The following graph from EcoWest is based on National Interagency Fire Center data.  The graph shows that people cause a third to nearly all wildfires depending upon U.S. region.  In other words, allowing more people to live in high risk areas can increase the likelihood of wildfires.

Why building codes and defensible space are not enough in wildfire high-risk areas

Many local governments have adopted building codes and other safeguards for new buildings in areas at high-risk for wildfire.  Safeguard examples include low-ignition roofing and other fire resistant construction material along with removal of nearby highly-combustible vegetation.  Unfortunately, researchers have found that these measures are insufficient in wildfire high-risk areas.

In The role of defensible space for residential structure protection during wildfires, researchers noted:

“The best long-term solution will involve a suite of prevention measures that include defensible space as well as building design approach, community education and proactive land use planning that limits exposure to fire.  Localized subdivision decisions emphasizing infill-type development patterns may significantly reduce fire risk in the future…” [Emphasis added]

In a 2018 letter to the San Diego County Board of Supervisors, the Center for Biological Diversity, noted:

“However, simply stating that the structures are built to fire code does not guarantee that fire threat will be reduced. Proper maintenance and upkeep of the structures themselves as well as the immediate surroundings (e.g., removing leaf litter from gutters and roofing; removing flammable materials like wood fences, overhanging tree branches, or trash cans away from the home) are required to reduce the chances of the structures burning. In addition, external sprinklers with an independent water source would reduce flammability of structures, yet none of the proposed developments include this feature on their structures. And while these fire-resistant structural features are important for fire safety and homeowners should be properly informed, the focus should be on retrofitting existing homes and structures in or near high fire-prone areas with these features, not putting these features on new homes that should not be placed in high fire-prone areas in the first place.” [Emphasis added]

Guiding Growth to Areas at Lower Risk for Wildfire

Growth, particularly new homes, should be guided to areas:

  • at low- to moderate-risk for wildfire,
  • with ample evacuation routes, and
  • where fire services are fully staffed and equipped.

Growth should be discouraged in areas with a high- or extreme-fire risk, particularly where evacuation routes and fire services are limited.

San Diego County, California provides an excellent example for what all local governments should do in areas at high risk for wildfire.  San Diego County General Plan Guiding Principle 5, makes it very difficult to build new homes in high risk areas.  This principle reads:

“New development should be located and designed to protect life and property from these and similar hazards. In high risk areas, development should be prohibited or restricted in type and/or density. In other areas, structures, properties, infrastructure, and other improvements should be designed to mitigate potential risks from these hazards.” [Emphasis added]

Following is an example of how a general plan can be designed to discourage sprawl into high-risk and other rural  areas.

The two figures below are from the 2019 Truckee Meadows Regional Plan.  The Classic Scenario on the left (Figure 2.3) shows how growth would continue to sprawl far from Reno, Nevada and other existing population centers.  The Infill Scenario to the right depicts how the same amount of development could be accommodated in Smart Growth areas located within or next to existing populated areas.  The Plan details the many benefits gained by the Infill-Smart Growth scenario vs. the Sprawl or Classic Scenario.

Are evacuation routes sufficient in areas at high-risk for wildfire?

Diasters, such as the 2018 Camp Fire that isolated Paradise, CA, focused a great deal of attention on the issue of evacuation routes.  In 2019, StreetLight Data released an analysis of evacuation routes for 30,000 U.S. towns.  The towns with the fewest evacuation routes and largest population generally were at highest risk, particularly if most of the residents used just one route to flee.

To view the national map of communities with limited evacuation routes visit: https://www.streetlightdata.com/limited-evacuation-routes-map/#emergency-map-response.

Emergency planners have considerable experience preparing for disasters like hurricanes where there’s usually days of advance notice. Wildfires, earthquakes, and other no-notice events have proven far more challenging.

If there’s a leading organization in the U.S. with regard to evacuation planning it is the Emergency Evacuation Committee of the Transportation Research Board (TRB), which is part of the National Academies of Sciences, Engineering, and Medicine.  A conversation with one committee member indicated that evacuation planning for no-notice events like wildfire is still in the developmental stage.

In webpages such as this one, CEDS usually provides examples of best practices.  Unfortunately, an example of a good wildfire evacuation plan does not appear to be available. There are guidance documents like the Federal Highway Administration’s Using Highways for No-Notice Evacuations. as well as Planning Considerations: Evacuation and Shelter-In-Place from the Federal Emergency Management Agency.

Growth in areas at high-risk of wildfire should be postponed until a no-notice evacuation plan proves that residents can safely escape regardless of the direction of an approaching wildfire.

Are fire services adequate for homes in areas at high risk for wildfire?

The National Fire Protection Association has established minimum response standards for career and volunteer departments.  For example, in rural areas (<500 people/sq mi), served by a volunteer department, a minimum of 6 staff must respond within 14 minutes.  This response time must be met for 80% of all events.  More stringent requirements apply to suburban-urban areas.

The Insurance Services Office (ISO) has rated more than 40,000 fire departments in the U.S.  The ISO rating is termed a Public Protection Classification (PPC).   The PPC rating ranges from the best “1” to “10”.  The rating is based on three factors:

  • Fire company staffing, equipment, maintenance, training, testing, etc.,
  • Water supply adequacy for fire suppression, and
  • Community risk reduction through safety education, fire investigation, and prevention.

If your home is served by a Fire Department with a rating of “1” then your insurance rates will be lower compared to the same home with a PPC of “10”.  More importantly though, the likelihood of loss of life and property may be higher in a community with a poor PPC rating.

The following graph shows that most fire departments have a PPC of 5 or better.  To see a graph for your state visit: https://www.isomitigation.com/ppc/program-works/facts-and-figures-about-ppc-codes-around-the-country/

Unfortunately, ISO only provides PPC ratings to fire departments and insurance companies; not the public.  However, a number of local governments provide this information to their residents in the form of plans and other documents.  Following are a few examples:

Before growth is allowed to sprawl into an area at high risk for wildfire you should insist that local officials demonstrate that the National Fire Protection Association standards will be met through a detailed plan such as a standards of cover document.

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