Community Wildfire Risk FAQ

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Find answers to frequently asked questions about community wildfire risk.

What is Community Risk? 

In addition to damaging residential properties, wildfires can impact day-to-day life within a community, cutting off access to utilities, emergency services, and transportation. The First Street Foundation Wildfire Model is used to determine the risk to infrastructure and properties based on the likelihood of direct wildfire impact or indirect exposure to embers from nearby wildfires. Exposure to wildfire is used to determine the amount of risk a community faces. The amount of risk each facility faces is based on its probability of being in a wildfire, its chance of burning, and exposure to embers

How are community areas defined? 

Community Risk denotes wildfire risk to the local services and infrastructure surrounding properties and is grouped by neighborhood, zip, city or municipalities, and counties. It considers wildfire risk across 4 different dimensions: (1) Infrastructure (utilities, airports, ports, and emergency services); (2) Residential properties; (3) Commercial properties; (4) Social services (churches, schools, museums). Because Community Risks can vary for different levels of geographies, Fire Factor® allows you to compare risks between these levels. 

Communities available through Community Risk overview:

  • Neighborhoods: Encompasses macro neighborhoods, neighborhoods, sub-neighborhoods, and residential districts (e.g. subdivisions and apartment complexes) are not an official designation and vary in size depending on local usage
  • Zipcodes: Zip code tabulation areas as provided by the U.S Census Bureau. 
  • Cities: Place (County Subdivision in New England) as provided by the US Census Bureau. Refer to a village, town, or city typically governed by a mayor and council.
  • Counties: are territorial divisions of a state and are typically government units that sit below the state level. County or county equivalents as provided by the US Census Bureau.

How do I read the Community Risk map? 

The Community Risk map allows you to easily visualize the geographic distribution of infrastructure and facilities at risk in your area. The map uses different colors to show how the level of wildfire risk varies between areas, with grey representing minimal risk and dark red showing extreme risk.

How can I compare risk between different locations? 

To compare the overall risk between your area and those around you, select "Compare areas." The map uses different colors to show how wildfire risk varies between neighboring areas. On one end of the spectrum, grey represents locations with minimal risk, while dark red shows locations with extreme risk. The map legend identifies the risk level each color on the map represents, making it easy to understand how the different colors relate to varying levels of risk.  

How can my home have minimal risk but my area has high wildfire risk? 

We understand it can be confusing if a property has a low Fire Factor yet Community Risk for your neighborhood is high. The distinction is that Fire Factors reflect the probability of a home being in a wildfire or its exposure to embers, while Community Risk determines the surrounding area’s vulnerability to wildfire. Community Risk encompasses the social risk, residential risk, commercial risk and risk to infrastructure of wildfire within a geographic area.A property's Fire Factor and Community Risk scores are both  comprehensive risk assessments, which take into consideration the 30 year risk of wildfires from direct wildfire impact or indirect exposure to embers from nearby wildfires. 

The First Street Foundation Wildfire Model is used to determine the risk to infrastructure and properties  based on the likelihood of direct wildfire impact or indirect exposure to embers from nearby wildfires. The amount of risk each facility faces is based on its probability of being in a wildfire, its chance of burning and exposure to embers. 

The probability of a facility being in a wildfire or its exposure to embers is used to determine the boundaries for each level of fire risk. Each category is given a ranking based on the percent of facilities that fall into each probability threshold. The overall Community Risk encompasses the social risk, residential risk, commercial risk and risk to infrastructure for a given area. Once risk is determined for each of the 4 categories, overall risk for a community is calculated by averaging the risk for all 4 categories. 

How does risk to commercial properties affect the community?

Wildfire damage to a commercial property can impact day to day life within a community and may impact the overall economic well-being of an area. Wildfire risk to commercial properties directly and indirectly threatens quality of life, access to and the ability to work, and general safety within a community. The Community Risk section can help convey risk to commercial properties in the surrounding community, ranking those risks from “minimal” to “extreme”. 

How does the number of residential properties with wildfire risk in my community affect me?

Due to the nature of fires and the ease in which they can spread under certain conditions, it's important to understand the risk to residential properties within your community.

Homes may be located in an area that is directly exposed to wildfire from nearby vegetation and fuel sources. For example, a home located adjacent to a densely wooded forest could experience impact from flames if that forest burns. Anything that can burn is fuel for a fire. This includes various plants such as grass, shrubs, trees, fallen trees and dead leaves. As this vegetation piles up, the chance of it burning, or fueling a fire, increases. The type of fuel sources impact how intense a fire is and how quickly it can spread under different weather conditions. While dry grass can catch fire and spread quickly with high winds, extremely intense fires tend to build more in dry dense vegetation areas where treetop canopies can ignite and cast embers several miles away.

Some homes are located in an area indirectly exposed to wildfire from embers. Embers are small pieces of material that remain after a fire and radiate a substantial amount of heat, and are light enough to be carried by the wind for long distances without being extinguished. A property in an urban area with little vegetation can be indirectly exposed to distant wildfire from embers carried aloft by the wind.

What facilities are considered public infrastructure?

Community Risk to public infrastructure includes utilities, emergency services, and transportation. 


  • Power station: Hydroelectric dams, fossil fuel (coal, natural gas, or oil), nuclear, solar, wind, geothermal, and biomass. For each plant type all structures and equipment on a given site are grouped together for each facility
  • Wastewater treatment: Facilities used to treat industrial wastewater and remove pollutants. Wastewater treatment plants use various processes (physical, chemical and biological) to treat industrial wastewater and remove pollutants. 
  • Superfund Site: Sites contaminated by hazardous waste being dumped, exposed in the open, or badly managed. Superfunds include manufacturing facilities, processing plants, landfills and mining sites. 

Emergency services 

  • Fire station: Facilities where fire engines and other fire equipment are housed. Fire stations accommodate functions such as housing, recreation, administration, training, community education, and hazardous materials storage. The data consists of building locations of fire stations, including those on military bases, airports, or manufacturing locations. 
  • Police station: Law Enforcement agencies that are publicly funded and employ at least one full-time or part-time sworn officer with general arrest powers. 
  • Hospitals: Facilities in which sick or injured people are given medical or surgical treatment. 


  • Seaport: Major U.S. port facilities, including commercial ports, along the U.S. coast, Great Lakes, and inland ports. This includes the location of a port’s waterfront facilities, including information on berthing, cranes, transit sheds, grain elevators, marine repair plants, fleeting areas, and docking and storage facilities. 
  • Airport: A defined area on land or water that is intended to be used either wholly, or in part, for the arrival; departure, and surface movement of aircraft/helicopters. 

What are social facilities?

Social risk assesses the effect of wildfire risk on social and cultural services. Community Risk to social infrastructure includes schools, historical buildings, government buildings, places of worship, and museums. 

  • Schools: Flood risk to all Public elementary and secondary education facilities in the United States as defined by the Common Core of Data  (CCD), National Center for Education Statistics (NCES ), and US Department of Education for the 2017-2018 school year.
  • Historical buildings: National historic places worthy of preservation. The National Register of Historic Places is the official list of America's historic and archeological resources. 
  • Government Buildings: All buildings or properties that are owned or leased by state-level governments. It includes buildings occupied by the headquarters of cabinet-level state government executive departments, legislative office buildings outside of the capitol building, offices, and courtrooms associated with the highest level of the judicial branch of the state government, and large multi-agency state office buildings.
  • Places of worship: Places of worship are 501(c)(3) non-profit organizations that are included in the IRS master files of public national records. 
  • Museums: Includes 278 university and general higher education museums, collections, and cultural heritage sites of scientific, artistic, and historic significance

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