Athena Has Taken the Guesswork out of Underwriting Wildfire Risk

Athena Intelligence
4 min readJun 2


Before discussing wildfires, the risk of property damage, the sources of data and the processing that results in Athena’s Voice of the Acre, we need to start with some basic information about wildfires. While large mega wildfires capture our imagination and scare property insurers, the majority of wildfires are surprisingly small.

A California Fire Marshall shared with Athena Intelligence that an estimated 90% of wildfires are small, averaging 3 acres. They will typically destroy the nearest structure before a fire engine can get to the scene. In a megafire, the focus is on defensible lines. In either case, distance from a fire hydrant, or a fire station is irrelevant.

Athena started with research about wildfires. There are number of academic institutions, government agencies and even interagency groups that do research into wildfire behavior. The vast majority of wildfires start in the uninhabited part of the wildland-urban interface (WUI).

Similarly, the vast majority of wildfires are caused by human activity. That is, campers or smokers in park areas, kids playing with matches in isolated areas, electrical transmission lines going over wooded hills or sparks from equipment.

While these fires change the ecosystem, economic damages occur in the inhabited area adjacent the uninhabited WUI.

So, among the first variables relate to the type and quantity of vegetation. The next set are focused on the density of the structures and the way the uninhabited and inhabited areas coming to contact.

We have shared the output of information about Clark County, WA through Tableau. The numbers quoted below can be found on sheet 2. (Tab Historical)

While most of these attributes are self explanatory, one of the key variables in the wildfire data is the Inhabited WUI categorization as Intermix or Interface. This is where houses and wild land vegetation meet or mingle.

In Clark county, Athena’s highest risk (Purple) Uninhabited land accounted for 24.44% of the wildfires that occurred over the period. And the high risk (Red) uninhabited land accounted for 17.70% of wildfires.

Photos from “Long-term Changed in the WUI …” by Dominic Kaim. Google

The picture above shows the intermix between the edge of the uninhabited and the relatively dense vegetation between the homes. Humans perceive this as a beautiful, lush neighborhood.

The picture below shows a nice neighborhood with a nearby park area, but a clean border. If these neighborhoods are typical, more money and effort is put into maintaining that clean border by the municipality. Intermixed neighborhoods typically see the vegetation near the home as the property owners’ responsibility.

The statistical evidence makes it clear that the overall vegetation in the neighborhood impacts the risk of every home in the neighborhood.

Again, using the Clark County data:

Areas with a risk profile of Purple - In the intermix the number of wildfires was 3.41% of the total. Interface accounted for 2.06% of the total burn areas.

In areas where the wild fire risk profile was Red — The intermix inhabited areas accounted for 1.39% of the total burnt areas. The interface inhabited areas represented 1.12% of all wildfire coverage during the period.

This is one of the many factors which Athena uses to evaluate wildfire conditions and risk. Other factors include the density of the structures, the vegetation type and growth rates, solar degree days and evapotranspiration (a measure of moisture and dryness that relate to fire risk).

Below is a picture of how housing density data impacts the Intermix vs. Interface information.

Intuitively, you know that fire would move more aggressively through the shrubs and trees around the homes in the low-density neighborhood. There are many ways all of the factors Athena considers interact to create a single risk score for underwriting wildfire.

This is part of an ongoing set of articles about Athena Intelligence’s Voice of the Acre®, focused on helping customers understand the 9 conditional flags of our single property report. These flags are summarized here.

Please see our other articles — we are working our way through the data on Clark County Washington as shown in Tableau. This discussion relates to the historic tab.

Athena Intelligence is a synthetic data vendor, to the insurance, utility and finance industries. The earth’s essential data is refined to make it easy for enterprises to use environmental information for future contracts, proprietary business decisions and risk management.



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