Environment
We all know wildfires have been getting worse in the drought-stricken western U.S., but experts say the growing risk on the east coast is concerning.
BySara Novak
Published January 29, 2024
When we think of wildfires, we often think of western states like California where massive blazes, such as the 2018 Camp Fire, have been among the deadliest and most destructive in modern history. In 2020, California’s worst wildfire year on record, 8,648 fires scorched 4.3 million acres of land.
While California and other western states face a high wildfire risk, the region’s wide expanses of wilderness are less likely to threaten humans. Not so in the eastern and southern United States, where population density puts more people and property at risk. According to the U.S. Census, 56 percent of the U.S. population lives in the eastern and southern regions of the country, compared to just 24 percent in the West.
New research shows that there may be cause for concern in the East as well, where fire size, numbers, and total area burned seem to be increasing.
Recently published in Geophysical Research Letters, researchers used data collected over a 36-year period to show that large wildfire numbers doubled from 2005-2018, compared to the two decades prior. The biggest increases were seen in the Southern Coastal Plains of Florida, portions of coastal Georgia, and South Carolina where the five largest wildfires occurred. Significant wildfires were also common in the Central Appalachian Mountains of Tennessee, West Virginia, and Virginia.
Conversely, wildfire numbers decreased in the northeastern U.S. as shifting climactic conditions led to more precipitation.
Why fires are increasing
The goal of the study was to identify whether wildfires were growing in frequency and scope, not to show what was causing this increase. But the authors speculate that warmer, drier conditions brought on by a changing climate combined with a lack of prescribed fires has led to a proliferation of woodier plants, trees, and shrubs that provide the fuel for fires to burn in greater strength and numbers.
“This makes for wildfire conditions that are much more difficult for us to suppress,” says Victoria Donovan, lead author of the study and an ecologist at the University of Florida’s West Florida Research and Education Center in Milton, Florida.
Invasive species like Cogongrass, a perennial weed capable of driving wildfires deeper into the forest, have also taken over large swaths of the South, across Alabama, Mississippi, and Florida. The grass increases the instances of wildfires because, once ignited, it burns hotter and faster and regrows more rapidly than native grasses.
Why wildfires in the East present greater risk
While the fires aren’t as large as they are in the West, the risk to humans is much greater.
“In the East we have a greater wildlife-urban interface, where we’ve seen more people intermingling with wild land vegetation,” says Donovan.
The study points to examples like the 2016 Gatlinburg fire in Tennessee, which, although less than a tenth of the size of the Camp Fire, destroyed nearly 2,500 structures and killed 14 people. When wildfires ignite in densely populated areas, they not only increase the risk of a loss of life, but also become harder to defend.
Additionally, the danger of wildfire smoke extends much farther than just the immediate area of the fire and can impact more people in the eastern U.S. Last year’s Canadian wildfires, for example, placed more than a third of the U.S. population under air quality advisories.
The study also found that 85 percent of wildfires were caused by humans, a statistic which isn’t surprising to Volker Radeloff, a forestry professor at the University of Wisconsin Madison who was not involved in the study. He says that when fires happen in populated areas, the risk of human ignition increases. People can start fires for any number of reasons, and in populated areas it puts the landscape at risk. They might be burning dead leaves in their backyard, and it gets out of hand—or, in the case of the Gatlinburg fire, two teenage boys playing with matches set the land ablaze.
“In these areas where houses and wildlife vegetation intermingle it’s kind of a double whammy because when a fire occurs lots of houses are at risk, you have to evacuate people, and there’s also more people to start fires either intentionally or unintentionally,” says Radeloff.
Planning for the unknown
While the study did show that the number of wildfires in the past four decades have increased, it’s challenging to point to trends because in the East, there’s still so much variability in the weather from year to year, says Loretta Mickley, a senior climate research fellow at Harvard, who was not involved in the study. “There will be one huge fire one year and then not much in the years to follow. You’re left wondering whether it’s a bad year or a trend,” she says.
While in the West you can see a clear upward trend in fires as precipitation decreases and temperatures increase, in the East the weather is less predictable. In an El Niño year, for example, the distribution of rainfall in the South and East may quell the risk of wildfires.
She says that the study is an “important first step” in showing us where we need to be taking care to protect the landscape.
And no matter whether it’s a trend or not, the numbers are concerning. “Right now, it’s safe to say that in the Eastern U.S. there are quite a few eco-regions that have had more fires in the last five to 10 years than in the decades before that,” says Radeloff.
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