A plant that's found everywhere is contributing to an escalating wildfire threat.

An ever-present, resilient plant is behind the surge in large, fast-spreading, and destructive wildfires across the United States.

Grass is as common as sunlight, and when conditions are right, it acts like gasoline for wildfires—one spark is all it takes for it to ignite.

Rising emissions are disrupting temperature and rainfall patterns, leading to more frequent and intense wildfires. These fires, in turn, fuel a destructive cycle, making grass the dominant player in the environment.

“No matter the environment, there's always a grass that can thrive there,” said Adam Mahood, a research ecologist with the U.S. Department of Agriculture. “Any 10-foot patch of land that isn’t paved will likely have grass growing on it.”

Grass fires, although usually less intense and shorter than forest fires, can spread much faster, outpace firefighting efforts, and encroach on the increasing number of homes being built near fire-prone areas, according to fire experts speaking with Dinogo.

In the past 30 years, the number of U.S. homes lost to wildfires has more than doubled as fires grow larger and more destructive. A recent study revealed that most of those homes were not destroyed by forest fires, but by grass and shrub fires spreading quickly.

The study found that the West is the most vulnerable region, where over two-thirds of the homes lost in the past 30 years were located. Of those, nearly 80% were consumed by grass and shrub fires.

One factor contributing to the problem is the growing trend of building homes closer to fire-prone wildlands, in what is known as the wildland-urban interface. The amount of land burning in these areas has skyrocketed since the 1990s, along with the number of homes. By 2020, approximately 44 million homes were situated in the interface, a 46% increase over the past 30 years, according to a recent study.

Building in fire-prone areas presents clear risks, but since humans are also responsible for igniting most fires, it significantly raises the likelihood that a fire will start in the first place.

More than 80,000 homes sit in the wildland-urban interface in the less populated regions of Kansas and Colorado, managed by Bill King. The U.S. Forest Service officer emphasized that living on the fringe of nature demands proactive measures to prevent disaster.

Property owners must take responsibility as well, as these fires can become so large and intense—and often wind-driven—that they may travel miles ahead, even with a substantial fuel break in place, said King.

‘A perfect storm’ for fire

Climate change-driven fires are now attacking the western United States from all directions.

“Globally, the areas that burn the most tend to have moderate rainfall,” said John Abatzoglou, a climate professor at the University of California, Merced. “It’s like the Goldilocks zone—just the right balance of wet and dry, with ample opportunities for ignition.”

In the American heartland, especially the dry and often windy Plains, a mix of extreme weather events throughout the seasons is creating perfect conditions for fires to thrive in the region's perennial grasses. Grass grows more abundantly here than in other parts of the U.S., providing a continuous source of fuel for fires.

The region is experiencing an increase in megafires like Texas's Smokehouse Creek Fire, the state's largest, as well as more devastating fires such as Colorado's Marshall Fire, which destroyed over 1,000 homes in 2021.

Rainy springs promote vigorous grass growth, which then goes dormant or appears dead in winter. Milder winters with less snow cover, particularly in the Northern Plains, expose the grass to warmer, drier conditions in late winter and early spring, according to King and fire weather expert Todd Lindley from the National Weather Service in Norman, Oklahoma.

Grass is particularly flammable due to its quick response to weather conditions, according to Lindley. Unlike forests, where long stretches of dry weather are needed to dry out the vegetation, grass can lose moisture in as little as an hour or even a day after rain. Add a spark, strong winds, and invasive shrubs that burn hotter and longer, and you have the perfect storm for a grass fire disaster.

“These compounded extremes—when they follow each other in the right sequence—can trigger a wildfire,” Abatzoglou explained. “Essentially, you’re setting the stage for a perfect storm of conditions that allow the fire to spread.”

Grass invasion

Years of forest neglect combined with extreme drought are fueling larger and more intense wildfires in the western U.S., according to King.

“When I started 30 years ago, a major fire was around 30,000 acres, and now that's considered normal,” said King. “Back then, I’d see one fire of that size every year or two, but now we’re seeing fires that burn over a million acres.”

Grass also exists within forest ecosystems, where it acts like a fuse, linking easily ignitable fuels to larger, drought-stricken trees, which intensifies and spreads the fire.

As trees die, grass takes over. Grass regenerates more quickly than other plants and can ignite again, often within months. King has witnessed this process firsthand.

“Green grasses can begin sprouting in a burned landscape within a day or two, that’s how rapidly they regenerate,” said King. “In contrast, forest recovery could take years, generations, or in some cases, might never recover in our lifetime.”

As wildfires continue to devastate the West, both native and nonnative grasses are taking over the land.

In desert areas, drought-driven fires are becoming more frequent and severe, fueled by annual grasses, which differ from the perennial grasses of the Plains, as they do not exist year-round, explained USDA’s Mahood.

These annual grasses quickly capitalize on rare rainfalls to grow, then die off, creating a blanket of fire fuel across the desert floor.

Two recent wildfires in California’s Mojave National Preserve serve as prime examples, according to Mahood. These fires exploited the invasive red brome grass, burning through hundreds of thousands of acres of Mojave Desert and destroying over a million iconic Joshua Trees.

Rising temperatures and drier conditions hinder the recovery of native plants, which leads to more grass growth.

Sagebrush, the West’s distinctive and essential plant, forms the largest ecosystem in the Lower 48 states. However, half of it has been lost or degraded in the past two decades. A USGS study found that each year, an area about the size of Delaware falls victim to grass invasions, fire, and other environmental pressures.

With the increase in grass and a complex web of climate-induced stressors, the risk of wildfires grows, both now and in the future.

“It may seem dire now, but in the next decade, it probably won’t look as bad,” Mahood said. “Think back to how bad the fire season was two decades ago – now, that seems almost insignificant.”