Assessing Your Home's Fire Risk Just Got Easier

I seldom leave my pocket of Northern California. But a few weekends ago, I traveled to the Bay Area to sort through some belongings I had left in the rental house I used to share with my now ex-husband and our son. I had only been on the road 20 minutes before everything I saw from the car’s windows began to look like wildfire fuel.

Part of the drive took us past the city of Vacaville, which sits nestled against the Vaca Hills. I could see the burn scar from a fire that erupted there just this past May, the second one to occur in the city within the last two years. The rental is in Martinez, in the scenic East Bay Hills, and as I looked around at the grasses, trees, shrubs, and transmission lines, it all registered as fuel to me—even the houses.

This year’s wildfire season is beginning to pick up speed and the fires are starting to feel a lot closer to home than they used to. Last month, a fire erupted about an hour north of me in a riparian zone in the Sacramento River Valley. It seemed unusual for a fire to break out there, where it’s typically wetter than most of the region. And it is, as climate scientist Daniel Swain noted:

I no longer trust that the agricultural lands and Yolo Bypass, which surround my city like a moat, will protect me from the threat of fire.

For all these reasons, I was eager to dig into a report on fire risks published last month by First Street Foundation. The group released this report in addition to the one they put out in 2020 on U.S. flood risks and it rates fire risks for individual properties located in every zip code across the U.S. And what it reveals is surprising. I wanted to learn more about current and future fire risks in my community and other parts of the country, so I reached out to First Street Foundation’s Chief Research Officer Jeremy Porter and Communications Director Michael Lopes to ask some questions. Their answers were illuminating and they also prompted more questions for me.

I’ve referred to your flood risk data extensively and am now equally impressed with the scope of the fire risk report and how you factored in weather, fuels, and ignition using the most current LANDFIRE information while also accounting for land-use changes. I’m wondering how you weighed each contributing factor. Did some carry more or less than others? For instance, how did current data on wind factor into assessing risk?

Dr. Jeremy Porter: The Fire behavior model incorporated a spread algorithm that used millions of past observed ignition locations as origin points for the start of fires and then we simulated millions of fires based on fuels and weather for today and into the future. The predominant drivers of the fire behavior model were the origin points and the surrounding fuels with the environmental conditions making the most impact as we scaled the model out into 2052. Wind was incorporated into the model based on historic observations to drive the fire's behavior but was held constant across time due to the lack of agreement on future wind patterns associated with climate.

It’s remarkable how you were able to apply the data to specific addresses and that this information is free to the public. What motivated you to develop a risk model to assess individual properties instead of just sticking with one based on community risk, such as Wildfire Risk to Communities?

Dr. Porter: The Wildfire Risk to Communities model is terrific for informing communities as to how they should be allocating resources to protect their residents from fire risk. However, the model does not give enough detail to individual property owners. As an organization, our goal is to make this type of information available to and accessible to individuals in order to make the implications of the changing environment personal to them. For that reason, we focus on property level perils.

I noticed what seems to me like a significant difference in the percentage of properties at risk of fire between the two primary zip codes in my home city, Davis, CA, especially by 2052. Davis is about 20 miles from any wildlands and is bordered by agricultural lands, a wetlands and wildlife area, and UC Davis. What could be causing fire risks to increase in urban areas like mine that are located outside of the perceived Wildland Urban Interface?

Dr. Porter: Our model is the first model to treat homes as "burnable" fuels. Due to that, the increasing exposure in the more urban areas generally allows for fire spread into the communities farther than past models have allowed for. This "home to home" ignition is generally the way in which more residential fires spread and is the primary way in which fires make it into residential areas in our models.

Did you factor in tree canopy and transmission lines in determining risks between different zip codes?

Michael Lopes: Tree canopy is certainly a source of wildfire transmission and spread. As for transmission lines, that's not something included in our model. The most likely impact of transmission lines would be as initial sparks for a wildfire, but our model doesn't necessarily look at the origination of wildfires, only how they might spread given certain conditions in certain areas.

I grew up on part of the Gulf Coast—a notoriously wet and humid place—and was stunned to see the number of properties that will be at risk there by 2052. What factors are contributing to this projected risk?

Dr. Porter: This is a much more common occurrence than people know. In Bay County Florida (Panama City) there have already been three fires big enough to require attention and evacuations. Additionally, when looking at the historic fire layers from MTBS, there are a tremendous number of fires from Texas up through the Carolinas along the coast. One of the more surprising things to me was the amount of fires in the Everglades that were captured by the historic wildfire database.

Michael Lopes: The South is mostly going to see a change over time, and it’s worth noting that we’re generally talking about much lower starting points in terms of risks, so the percent changes are much higher than they are in the West, where the aggregate risk is obviously far larger than in the South.

I would have thought that the Berkeley Hills would have been at far greater risk than your report suggests, as well as the area in Santa Rosa where the Tubbs Fire occurred. Why doesn’t the risk on paper line up with what we’ve seen on the ground in recent years? When I typed in an address affected by the Tubbs Fire, I found the fire risk to be minor. Would you mind telling me more about that?

Dr. Porter: The risk layers are probabilities based on the inputs to the layer and the fire behavior model. They won’t always line up exactly with what we see on the ground, but for the most part, it will show risk where historic fires have occurred. We have been comparing our layers to maps of fires that have occurred historically and that have occurred in the past couple of fire seasons and they generally show risk. A minor risk is still risk and should be taken seriously. It doesn’t mean that there is no risk, just that the conditions are less probable than other places in our model. It is not that dissimilar to flood risk. Hurricane Sandy flooded much of lower Manhattan but the flood risk there is actually relatively low. Yet, anyone who lives there probably thinks their risk is higher because of that experience.

Do you have any insights to share with people who are looking at the maps and having trouble understanding why their homes or neighborhoods are at higher risk than they were expecting and how much of it has to do with climate change?

Dr. Porter: Most of the comments we are receiving are actually the opposite in that folks equate evacuation orders, smoke, and nearby fires with high risk …  but their actual properties might be at lowered risk. Due to that, we are hearing from a lot of folks who think their risk should be higher. If people think their risk is too low, I'd relate that to the fact that these are probabilities of wildfire, not a certainty, and that for the most part, the residents are likely aware of nearby fires that have occurred in recent years.

What is the most important takeaway message you would like to give people about climate change, fire risk, and protecting lives and property? Do you expect to see people moving or changing their buying and renting choices based on this information?

Dr. Porter: The most important takeaway is that there is significant fire risk today and that is going to nearly double in the next 30 years. We don't expect folks to move or change behaviors around where they will live, but we hope that the information and solutions allow people to better protect themselves from the risk they may have.

How often do you plan to update the maps? Are there any risk factors you might give additional or less weight to as warming continues and conditions on the ground evolve?

We are updating our maps every year with the most up-to-date fuel layers, recent wildfires, and other information to ensure they stay up to date with recent fire activity, available fuels, and climate information driving the wildfires. We are also actively addressing customer feedback and constantly investigating potential issues with the model.

If you’re following the news about the climate crisis, you probably know that it’s not just fires that will become more widespread. The number of heatwaves, droughts, and floods—like the devastating one that happened in Yellowstone last month—will increase, too. Historically wetter places, like the Northern Plains and the Northeast, will also experience an uptick in flash droughts, writes Imtiaz Rangwala in The Conversation. And scientists project that the muggy southern states will see more extreme droughts as warming continues, according to a study in Science Advances.  

Though I’ve tried to keep up with as much climate news as possible, it’s only natural that I would know a lot more about what a warming world will mean in my own home state. A lot is happening here in California! But my goal in starting this project is to learn more about the places other people call home—the people, plants, animals, and fungi and lichen; the rivers, seas, mountains, prairies, and deserts—with a focus on the U.S.

What will your state or region look and feel like as temperatures rise? What kinds of hazards do you need to plan for, and which areas might be worth abandoning altogether? I’ll share what I learn in posts and a periodic newsletter. But one of my most ambitious goals is to publish a detailed story about every region in the country by the end of next summer. If things go as planned, I also have a second goal I would like to see happen and will let you know more about it soon.

Though my main focus will be on climate change in the U.S., you can also expect to see summaries of climate news from around the world, along with other topics, such as COVID, economics, and any other science-related developments that look interesting. I’ll post these at the bottom of my weekly newsletter. For more information on my plans for this project and to learn more about me, see my about page.

It might seem provincial to focus on the U.S., but I see value in zeroing in on more familiar regions as a way to make the climate crisis—a vast, abstract concept for many—more real. It was my interest in local climate impacts, such as the possibility that parts of Sacramento will likely be flooded due to sea level rise within this century, that connected me to what’s globally occurring. Climate change isn’t something that’s happening elsewhere; everyone will eventually feel its effects.

Am I hoping to somehow make a difference? I admit that’s true, though I’m not naive. It’s unlikely that anything I share here will influence you to accept the science behind human-caused climate change if you haven’t already done so, and even more importantly, to accept the urgency with which we need to address it.  And yet, I still find myself driven to give as many people as possible a glimpse of what our country will look and feel like under hotter temperatures, even as we experience political and ideological divisions the likes of which I have never seen in all my 62 trips around the sun. My hope is to inspire action, but what you do with this information is up to you. Welcome to The States Climate Project.

Here’s what else is happening.

Other Climate News

•From Yale Climate Connections: Scientists collected pollen data in Atlanta, Georgia, and “found that, on average, tree pollen seasons are starting earlier and getting longer. Average daily pollen concentrations [have] also increased over the years.” The evidence, scientists say, increasingly points to a warmer climate as being a major culprit behind the increased pollen levels.

•What happens when trees in colder regions don’t adapt well to warmer temperatures? To help preserve tree coverage in these areas, our forests may need some help from humans. At the University of Minnesota, Julie Etterson’s project is helping trees migrate farther northward. “About 10 years ago, we started this work where we took species that are predicted to do well with climate change—local populations and populations from further south—and planted them up into the northeast corner of Minnesota,” she told the Yale Climate Connections team. The project has been a success, with the seedlings from the southern part of the state faring better in their new northerly environment than the ones from localized species. This could help “retain forest cover and increase forest resilience” in other parts of Minnesota, Etterson said.

•As the Supreme Court takes an ever-increasing conservative bent, as evidenced by West Virginia v. the E.P.A. and other recent cases, Bill McKibben writes in The New Yorker, “The conservative drive to roll back federal power has long since become more ideological than practical; the right-wind luminary Grover Norquist … said that he wanted to shrink the federal government to a size that he could then ‘drown in a bathtub.’ But drowning whole communities as the sea level inexorably rises?” But since Obama’s Clean Power Plan was challenged in courts and, ultimately, never implemented—it gave the E.P.A. the authority to more broadly regulate carbon emissions across states—it’s not as if we’ve lost the golden prize, as David Wallace-Wells weighs in on the Supreme Court’s recent decision in The New York Times: “This is all terrible. But it isn’t much changed by West Virginia v. E.P.A. either. U.S. emissions are not likely to rise. The powers the judgment restricts were never actually exercised under the Clean Power Plan.” For a plain-language summary on what the ruling means, I recommend Robinson Meyer’s interview with Michael Wara in The Atlantic.

What I’m reading

This must-read piece by Peter Brannen in The Atlantic on the life and death of Fred the mastodon filled me with wonder, and also sadness for how humans have since altered the world above Fred’s burial grounds in ways that threaten the survival of countless species. “Written in bone are 13,200-year-old memories of a mastodon living in the twilight days of his species. He migrated across the Midwest with the seasons, living in a world about to change forever.” What memories will be written in our bones and the bones of other animals, given today’s vast and fast-paced climatic changes? Unlike Fred, we have the capacity to shape the story’s trajectory.