Most Wildfires Aren’t Forest Fires

The fire was “fueled by drought and hurricane-force winds.” It “jumped from one home to the next,” the local news later reported, and “moved in unpredictable and unprecedented ways.” Camera phone videos showed shaky scenes of last-minute evacuations — a “dizzyingly chaotic display of improvisation and panic.” The fire had apparently ignited in dry invasive grasses outside of town, perhaps due to a downed power line, before blowing into an unstoppable “urban firestorm.” Airborne embers destroyed hundreds of structures, leaving behind ashen ruins that survivors said looked like a war zone.

It was December 30, 2021. The Marshall fire would become the most destructive in Colorado’s history, ultimately killing two people, causing 35,000 to flee, and destroying more than 1,000 homes and businesses outside of Boulder. But to an untrained eye, the landscape hardly looked like a place where a wildfire could break out; after all, there was no forest. “It was 200 yards from a Costco — why would I have to worry about fire?” one survivor recounted to The Washington Post afterward. “It’s, like, suburbia, you know?”

But grass fires are a growing danger in the United States, even if they lack the iconic imagery of the forest fires that tend to dominate the news this time of year. The 2018 Martin fire in Nevada, the largest in the state’s history, burned 435,000 acres of invasive cheatgrass and at one point stretched 54 miles long. The 2006 East Amarillo Complex fire in Texas blackened almost a million acres. And the wildfires in Maui this month were the deadliest in modern U.S. history, in part because they ignited in highly flammable non-native grasses, which burn hot, fast, and unpredictably.

“They’re too intense for firefighters to get next to with either ‘dozers or engines,” Brad Smith, the Predictive Services department head at Texas A&M Forest Service, told me of the wind-driven grass fires he sees across Texas. “They also move too fast, so it’s dangerous to put people out in front of these fires. It’s often the case we have to wait either for the weather to change or for the fire to move into a more favorable fuel type,” such as plowed agricultural land, before first responders can get it under control.

I had reached out to Smith after seeing him dispense grassland firefighting advice in a 2011 educational video for firefighters titled, “Oh, It’s Just a Grass Fire.” Produced by the Wildland Fire Lessons Learned Center — a grimly named government agency that exists to “share lessons and knowledge within the entire wildland fire community” — the video was apparently intended to head off dismissals of what it calls a “potentially underestimated fuel type.”

Such an underestimation in the industry comes from the fact that grass fires can actually have “a few advantages” for wildland firefighters, as authors Justin Angle and Nick Mott write in their forthcoming guide This Is Wildfire. “There are a lot of fire-fighting strategies that are just more feasible in a grassy landscape that’s more open and has more fuel breaks like roads and bodies of water,” the authors go on to explain. “In addition, the fuel type is more homogenous (and therefore predictable) compared with a mountain ecosystem.”

But throw in high winds, and all of a sudden grassland fires can become a completely different beast. “People think [wildfires] just move in one direction, but winds generally quarter,” Smith said. “So let’s say you have a north wind; you think, Well, [the fire] is going south. But if you get a 45-degree change in direction, that fire can move left or right for short periods of time very quickly. That can catch people by surprise.” In the instructional video, this point is made with the cautionary tale of Destry Horton, a father of two who was killed fighting a grass fire in Oklahoma in 2006.

But if even firefighters need the occasional somber refresher to take grass fires seriously, then many of the rest of us have likely barely registered them as a threat. “I think a lot of people look at a grass fire and feel like, ‘Well, I could just go stomp it out,’” Barb Satink Wolfson, the University of California’s Cooperative Extension fire advisor for Monterey, San Benito, Santa Clara, and Santa Cruz counties, told me.

Perhaps that’s partially because “forest fire” is often interchanged with “wildfire,” inadvertently evoking the conflagration out of Bambi: popping evergreen trees, flames reaching for the sky, adorable woodland animals running for cover. Reality looks a little different: Grassland pasture and range make up 60% of land use in the Mountain West and about 29% of land use in the Pacific Coast states, the most recent survey by the United States Department of Agriculture found (compared to 18% and 29% forest-use land, respectively).

Fire statistics seem to bear that out: In a study of burns in 11 western states between 1984 and 2020, only 35% were actually in forests, Denver’s 5280 magazine reports. In another cited study, local fire departments “responded to forest fires just 7% of the time, compared to 39% for grass fires.” Smith also told me that of the 30 largest fires in Texas since 2000, 28 had “occurred in our grass-dominant fuel-scape in West Texas.”

The tragic consequence of the public not taking grass fires seriously — or not knowing to take them seriously — is that many people who live in wildland-urban interface communities near or adjacent to natural, undeveloped lands might not have made the proper wildfire preparations or have an evacuation plan because the fire threat feels remote.

That can prove deadly. A quarter of Hawaii is covered in highly flammable non-native grasses and “virtually every community [in the state] is on a wildland-urban interface,” one fire manager recently told Wired. Yet the communities were unsuspecting and unprepared for the fire that swept through Lahaina and the surrounding landscape last week. Part of that is because fire is “not something that has been a part of ... society in Hawaii,” Satink Wolfson said, adding: “There isn’t a big history of people telling [residents]: ‘You need metal gutters, you need to make your home fire safe.’”

Though fire is not a historic part of the ecology of Hawaii, it is in North American grasslands, where Indigenous communities have practiced cultural burning for centuries upon centuries. But non-native grass species are likewise disrupting these natural cycles in the western United States, since invasive plants tend to grow thickly and contiguously, unlike native perennials that grow in more isolated clumps that help naturally break up fires. By one estimate, invasive grasses can more than triple a region’s susceptibility to wildfire.

Making matters worse, non-native grasses tend to quickly colonize and outcompete native plants after burns, in effect bridging fire further and further into landscapes where it doesn’t belong, such as deserts — or urban environments. “Those non-native herbaceous species are like the wick,” Max Moritz, a Cooperative Extension wildfire specialist and adjunct professor at U.C. Santa Barbara’s Bren School of Environmental Science & Management, told me. “They’re the place that fire can get a foothold on the landscape, even if the landscape wasn’t supposed to burn very often from a fire ecology perspective.”

Increasingly, attention in the West has focused on allowing “good fires” to run their course — grass fires included. “I would love to see CalFire use natural ignitions to reduce fire hazard and to improve ecosystem health,” Satink Wolfson said. “I’ve already seen so many fires put out this year that could have had a positive impact.” Moritz’s focus is on better land-use planning, including rehabilitating abandoned farmlands into working buffer zones. Both Satink Wolfson and Moritz floated strategic grazing as another possibility. But everyone agrees: Something needs to be done.

“Grasslands — there’s a lot of area there to manage if you are hoping to reduce the ignition potential,” Moritz said, then ominously warned: “It’s almost all ignitable.”

Read more about grass fires:

How Invasive Plants Fueled an Inferno in Maui