WUI & Indexing Wildfire Risk

Athena Intelligence
5 min readFeb 8, 2024

Wildland Urban Interface Describes Risk Factors, but Not Risk of Destruction

The vast majority of wildfires are caused by human activity. However, the fires typically originate in uninhabited areas near where people live or work, a zone referred to in wildfire circles as the Wildland-Urban Interface (WUI). This is because, while some wildfires are caused by lightning, more common ignition events include sparks from equipment, campfires, and smokers in park areas, as well as electrical transmission lines in wooded areas and children playing with matches.

What is the WUI? (fema.gov)

Within the continental United States, the WUI is defined, described, and made available to risk modelers by the U.S. Forestry Service. The information on the WUI includes distance, the type and quantity of vegetation, and the way uninhabited and inhabited areas come into contact. Most property insurance companies and risk modelers use this WUI information provided by the government as a set of descriptions of risk factors.

Side note focusing on how the components of the WUI are used:

Before describing these risk factors and why they matter, I want to delve into that last sentence.

Most risk modelers utilize the WUI as provided by the government, employing it as a set of descriptions outlining risk factors. They generate an index or stack of information, akin to what Yahoo! was doing in Internet search 30 years ago.

Athena takes these descriptors and converts them into a profile for each property, assigning a probability to the occurrence of a wildfire. Profiling, or leveraging the relationships between data points, was the concept Google used to enter the Internet search market 25 years ago. This innovation changed how people engaged with search and was a factor in the growth of overall Internet usage in the early 2000's.

Athena’s Voice of the Acre® has been optimized for economic losses, so risk associated with proximity to WUI is included in property profiles, along with other aspects of the land’s propensity to host a fire.

What is in the WUI?

The Wildland Urban Interface is the area where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels. The WUI serves as both the location and the description of the zone in and around property with significant vegetation, which can increase the risk of a wildfire.

Globally, the WUI encompasses only 4.7% of the Earth’s land surface, yet nearly half the population (3.5 billion people) resides in close proximity to one. The WUI is particularly prevalent in Europe, covering 15% of the land area. Looking at the people whose lives were affected by wildfires from 2003 to 2020, approximately 400 million people, two-thirds of whom were living in a WUI area, experienced the impact.

For risk modelers, the WUI comprises four major components used in evaluating wildfire risk to a structure, vis-a-vis the WUI. They include:

  • Unihabited/Inhabited — Most fires start in uninhabited areas, but the majority of economic damage occurs in inhabited areas. Athena is optimized to focus on economic losses.
  • Population Density — The data categorizes structures into low density, medium density, and high density, influencing both economic losses and the likelihood of wildfires. For instance, a low-density neighborhood near burning wildlands is more likely to be in the fire’s expansion path than a row of tall apartment buildings.
  • Location/Distance — Most models put a heavy emphasis on the distance between a structure and the wildland. While on the surface this seems obvious, it doesn’t align with reality where embers can move miles is minutes. Understanding a location’s risk, in the context of topography and all the factors that influence fire within several miles, is necessary to accurately assess wildfire risk.
  • Intermix and Interface — The vegetation in the inhabited nature, which is closely tied to the population density, is the single most important factor in the wildfire risk. This is worth a few paragraphs of discussion.

Fire comes in multiple “flavors,” and a future wildfire is described by the conditional flame length, heat, intensity of the burn, and other descriptors in the USFS Wildfire Hazard Potential (WHP) maps. These descriptors are all derived from the expected fuel type, which, in turn, is tied to the vegetation in the Inhabited WUI — categorized as Intermix or Interface. Intermix properties have a higher associated risk.

The picture on the left shows an WUI Intermix area. Homes are close to an uninhabited area and there is relatively dense vegetation between the homes. Humans perceive this as a beautiful, lush neighborhood, where vegetation near the home as the property owners’ responsibility.

In contrast, the picture on the right depicts a neighborhood with an Interface adjacent to a nearby park area. This means there is close proximity to the wildlands but with a clear and well-maintained border. If this neighborhood is representative, the town or city has staff dedicated to maintaining the park and ensuring the upkeep of that border. Interface WUI neighborhoods generally carry a lower risk of wildfire damage compared to Intermix WUI neighborhoods.

Most wildfire risk models stack or describe these 4 factors to create an index of wildfire risk. However, a description is distinct from probabilities or insights into the damage risk. Gaining such insights necessitates an understanding of how these factors, along with several dozen others, interact and correlate. Athena’s Voice of the Acre® is an artificial intelligence algorithm that generates dozens of internally used correlations and derivatives. These derivatives are employed to construct a profile of the land’s inclination to support a fire.

A Voice of the Acre® profile, of a single property or aggregated into an area for a GIS report, in the context of all the nearby profiles, offers this is a probabilistic projection of wildfire risk, for the property and the neighborhood.

For power companies (generators and operators of transmission and distribution systems) and municipalities can use these profiles to assess, a year in advance, where a consequential fire is most likely. Similarly, insurance or financial services companies and use property profiles in underwriting, portfolio risk optimization and loss cost probabilities for reserving.

Athena Intelligence is a data vendor with a geospatial, conditional, profiling tool that pulls together vast amounts of disaggregated wildfire and environmental data to generate spatial intelligence, resulting in a digital fingerprint of wildfire risk.

Contact us at info@Project-Athena.com and follow us here.



Athena Intelligence

Athena Intelligence weaves vast amounts of disaggregated environmental data. Drop us a line (Info@Project-Athena.com), or visit www.athenaintel.io