May 16, 2022 - Energy & Environment

Where homes will face the most wildfire risk in next 30 years

Projected percentage increase in properties with a moderate risk of burning
Note: Moderate risk is defined as having between 1-6% chance of experiencing a wildfire during the next 30 years; Data: First Street Foundation; Chart: Erin Davis/Axios Visuals

New research shows climate change will cause a steep increase in the exposure of U.S. properties to wildfire risks during the next 30 years, doubling the risk level in many areas.

Why it matters: While broad trends in wildfire risks have become clear, this is the first time probability-based wildfire risk data will be made available to property owners and prospective owners to help them make informed decisions.

Driving the news: With wildfires already raging across the West, scientists have shown clear links between human-driven climate change and escalating wildfire intensity, frequency and size. In addition, the seasonal timing of wildfires is shifting in many states, with fires lasting later into the fall and beginning earlier in the spring.

Zoom in: The new report and its accompanying tool come from the nonprofit First Street Foundation, known for mapping flood risks.

  • Its new "Fire Factor" risk score seeks to capture the changing risk profile of individual properties as global warming continues, both in terms of exposure to a wildfire and shifts in wildfire intensity.
  • In a report accompanying the Fire Factor release, the researchers present the state-by-state findings from its new peer-reviewed, open source risk model, which projects wildfire risk out to 30 years — the span of a typical mortgage.
  • It finds that many properties currently at risk of fire will see their wildfire risk double during the next 30 years, due to the effects of climate change.

Details: The report finds that a total of about 80 million properties are at some level of wildfire risk during the next three decades. Of these, 20.2 million properties face "moderate" risk, which is defined as having up to a 6% chance of experiencing a wildfire during the next 30 years.

  • About 6 million properties face a "major" risk, which is a 6%-14% risk of a wildfire.
  • About 1.5 million properties face "extreme" risk, which is defined as a greater than 26% risk during the period.
  • A total of 49.4 million properties face a cumulative burn probability of less than 1% over the next three decades, for a "minor risk."

Threat level: According to the report, the states with the largest amounts of properties at risk include: California, Texas, Florida, Arizona and Oklahoma.

  • The states with the largest increase in properties with minor risk or greater during the next 30 years are Colorado, Alabama, Mississippi, Texas and Montana. Many southeastern states would also see an increase in wildfire risk.
  • "The thing that we noticed right away was the amount of risk that's in Texas, Florida, in places outside the typical wildfire areas," Matthew Eby, founder and executive director of the First Street Foundation, told Axios.
  • Climate change is also expected to move many properties from the moderate to major risk categories, a trend the report describes as a "looming catastrophe."
  • Wyoming, Arizona, New Mexico and Utah would see the biggest increases in properties with major wildfire risk by 2052.

Between the lines: The open source nature of the modeling stands out from many climate intelligence firms that approach similar problems using proprietary methods, sometimes referred to as "black box" models since their data and methods are semi-hidden.

How they did it: To arrive at the results, the model simulated fire behavior millions of times, capturing a probabilistic view of how a wildfire could move across the landscape under different conditions. It also includes information on wildfire intensity (how hot flames will be when they reach a property), and how this may change over time.

  • This intensity metric can be useful for property vulnerability assessments that could encourage property owners to take risk reduction measures, like changing a home's roof type to one that is more fire resistant and clearing nearby vegetation to increase the defensible space.
  • The "Fire Factor" risk score will be included on a dedicated website and be integrated across residential real estate listing sites like realtor.com and commercial property services such as Crexi.

What they're saying: "A little more than one out of two single family homes across the country has at least some wildfire risks," Sara Brinton, lead product manager for realtor.com, told Axios. "We think it's important for every American to have access to this type of information."

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