Much of the western United States is one unlucky lightning strike or misplaced ember away from a major wildfire, thanks to a rare and dangerous combination of climate conditions.
The huge wildfires currently burning across California and Oregon are the result of a mix of a historic drought, extreme heat and several other conditions that have the area primed to burn, scientists and fire experts say. And with more heat and dry weather expected in the coming months, this fire season could be worse than any in recent times.
An NBC News analysis of 30 years of fire risk data shows that the heat dome that baked much of the region in late June was the final ingredient needed for explosive fire risk. This heat, on the heels of an extremely dry winter and spring, and in some places a few such such years, took the region from dry to even drier, allowing even the smallest spark to ignite a conflagration. This has led to a higher than average number of fires in the region so far this year.
The Energy Release Component, an index compiled by a collection of government agencies called the National Wildlife Coordinating Group that takes into account plant moisture conditions and is used by fire scientists to gauge fire risk, spiked significantly above average in several states prone to forest fires, including California, Idaho, Montana, Oregon and Washington, following the record-breaking temperatures in late June. Experts say this shows that the conditions were ripe for the early, strong start to the wildfire season.
“I like to think about the ingredients of fire being somewhat similar to the ingredients you need to start a campfire,” said John Abatzoglou, an associate professor at the University of California Merced’s Climatology Lab. “You need enough fuel, some fine fuels [kindling, flammable plant matter], you need that fuel to be dry enough, and you need an ignition source to bring all those three things together and you have what it takes for a fire.”
In 2021 all of the ingredients have come together, leaving the region ready for a fire.
“The West is a tinderbox this year,” Abatzoglou said.
The high heat and dry weather have led to conditions on the ground throughout the Northwest that are normally seen much later in a typical fire season.
“We're seeing fire behavior that we typically don't see until the middle of August,” said Josh Harvey, the fire management bureau chief at the Idaho Department of Lands.
Trees wet enough to resist the heat of an ignition usually help slow the spread of fires, experts say. Firefighters in Oregon say the conditions on the ground are so dry that even large trees are contributing to the spread.
“It’s almost as if the trees are going up like grass,” said Jim Gersbach, a spokesperson at the Oregon Department of Forestry. “They’re going up that quickly and instantly torching, because the needles don’t have much moisture.”
What starts a fire can be random, Abatzoglou said, pointing to lightning storms or accidental sparks from gender-reveal parties. But the conditions must be right for the fire to see explosive growth.
“What we’re seeing, at least during years like this, is it’s dry for a long period of the year and over a large geographic area,” Abatzoglou said. “It’s those extra spins on that roulette wheel that increase the potential for fires to find their way to burn on the landscape.”
Forests are also much denser due to the practice of putting out all wildfires for much of the last century, regardless of their threat to people. A dense forest requires more water to stay healthy, leaving it more likely to dry out and kindle an explosive fire.
“Because of the way we’ve managed the forests, we’ve set up the conditions for fires to be more severe,” said Donald Falk, a professor at the University of Arizona School of Natural Resources and the Environment. “That’s on us. We’ve prevented fire from doing its job.”
Even before the Beckwourth Complex Fire in California and the Bootleg Fire in Oregon exploded in size, firefighters this year have dealt with an abnormally high number of smaller fires.
In Oregon, Gersbach said that firefighters have battled 68 percent more fires so far this year than average. And it’s not just Oregon: much of the western and northwestern U.S. has also been home to a significantly higher number of fire starts.
With many states in the Northwest seeing similarly unprecedented and severe conditions, resources are running thin.
“When we talk about resources available to fight these fires, the system is tapped,” said Harvey, from the Idaho Department of Lands. “There’s just not much out there.”
Overstretched staffs make it more likely for small fires that would have been otherwise contained to grow out of control, Harvey said.
Strong, consistent rains are what ends fire seasons, experts say. With the highest temperatures of a typical calendar year most likely yet to arrive, wildfires will get worse unless rainfall arrives.
“We just don’t have a great reason to believe that’s going to happen,” Abatzoglou said.
If strong winds arrive before the rains, an already bad fire season could become disastrous. Abatzoglou said that when wind hits a fire, especially in a drought, “you can get upwards of a half million acres in a couple days.”
Experts say changes in the region’s climate mean that conditions will be increasingly ripe for fires.
“What we do appreciate is that Oregon and much of the western United States is experiencing the cumulative effects of multiple years of drought, and that’s having an impact on fire frequency and intensity,” Gersbach said. “This is something of a new normal.”
