It's something of a Golden State paradox: Dry winters can pave the way for dangerous fire seasons fueled by dead vegetation, but wet winters — like the one the state has seen so far — can also spell danger by spurring heaps of new growth that can later act as fuel for flames.
Experts say it's too soon to know with certainty what the upcoming fire season has in store. The atmospheric rivers that pounded California in January have left the state snow-capped and wet, which could be a fire deterrent if soils stay damp.
Shoppers navigate heavy rain in a Costco parking lot in Rancho Cucamonga in early January.
But if no more rains arrive — or if other, less predictable factors such as lightning storms and heat waves develop later in the year — all that progress could go out the window.
"The dice are loaded for a weak fire season, but there are multiple things that could cause it to go the other way," said Park Williams, a bioclimatologist at UCLA.
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There's no question the recent rains offered some relief. The storms moved most of California out of the extreme drought categories in which it has been mired for more than three years, and portions of the Sierra Nevada are still buried under multiple feet of snow.
But lower-elevation areas could be at risk, Williams said. That includes the hills around Los Angeles and the foothills of the Sierra Nevada and northern coastal ranges, which are bursting with new grasses that can easily dry out.
"This year, we've loaded up the ground with a whole bunch of new vegetation, and so in summertime — as long as the summer is hot and dry — the probability of grass fires is probably higher this year than normal," he said.
Capt. Robert Foxworthy, a spokesman for the California Department of Forestry and Fire Protection, said he was so far "optimistic" about the season in higher-elevation areas, where the month ended wetter than in recent years. In 2021, dry conditions paved the way for the Dixie and Caldor fires to become the first to ever burn from one side of the Sierra to the other.
Rick Fitzpatrick holds a dog after evacuating from the Fairview Fire Monday, Sept. 5, 2022, near Hemet, Calif. (AP Photo/Ethan Swope)
"Obviously, the more moisture we get, the better we're going to be," Foxworthy said. "The more snowpack we have, the better chance we have of it being a quieter fire season overall."
But much depends on whether the rest of the wet season brings more rain, he said. Seasonal forecasts are currently inconclusive, pointing to equal chances of dryness or wetness in much of California through April.
If no more rain falls, and if temperatures rise and strong winds arrive, "then I think we'll be in a completely different place come summertime," he said.
What's more, moisture is only one ingredient in how fire season develops. Many blazes are triggered by heat, lightning, winds and other factors that are harder to predict in advance.
"I can't tell you how many people are going to drive down the road dragging a chain behind their vehicle that may start a couple of fires. I can't tell you if we're going to get a big lightning outbreak ... that's going to drop 15,000 lightning strikes in two days, starting a bunch of fires," Foxworthy said.
There are other factors as well. Many of California's largest fires in recent years have started during intense heat waves, which are becoming hotter, longer and more frequent due to global warming, increasing their likelihood of contributing to conflagrations, said Williams.
NBC reports that the United States government is boosting its efforts to protect vulnerable areas of the country from devastating wildfires.
Climate change is also contributing to worsening aridification and evapotranspiration, or the processes by which the state's atmosphere is becoming thirstier and sapping more moisture from plants and soil.
"The atmosphere is going to be faster to take the water back, because the air is warmer and more arid," Williams said. "And so this spring, evaporation rates will be higher than they would have been given the same winter storms in a cooler world."
Also in the mix is the anticipated arrival of El Niño later this year, said Paul Pastelok, senior meteorologist and lead long-range forecaster at Accuweather. El Niño — a warming of sea-surface temperatures in the tropical Pacific — is often associated with wet conditions in the state, especially in Southern California.
Pastelok said an El Niño pattern could pull more moisture into Southern California in fall and winter, potentially holding back the fire season. But its biggest effect would probably be felt next year as it dampens soils and spurs new growth once again.
The main concern for this year is the timing of the dryness, he said. In fact, the wet start to January could simply push the beginning of fire season later.
"What we notice is at higher elevations, these kind of wet, snowy rushes tend to delay the fire season — it tends to get put off until later-than-normal time periods, probably toward the fall," Pastelok said. "Whereas the lower elevations, it really doesn't matter much. The soils will dry out quickly, the dry fuels will come on strong as long as there's no interruptions."
Last year's season also proved how unpredictable fire in the West can be. The state started the year with record dryness, and all signs were pointing to another bad season. Drought-driven fire seasons in 2020 and 2021 broke records, burning 4.4 million and 2.6 million acres, respectively.
That forecast largely failed to manifest in 2022, with the year delivering one of the weaker seasons in recent memory, 364,000 acres.
That was thanks largely to some well-timed rains that helped dampen burgeoning blazes, as well as a lack of "trigger mechanisms" such as lightning storms and strong wind events, Pastelok said.
How wildfires have worsened in recent decades
How wildfires have worsened in recent decades
Earlier this month, residents throughout the Northeast woke to hazy orange skies as smoke blew down from a nearly 12-million-acre wildfire burning in Quebec, threatening national forests and property throughout the province. Thirteen American states issued air quality alerts, highlighting the impact of large-scale fires beyond their immediate path.
Wildfires are innate to forest ecosystems, clearing out dead debris and paving the way for new growth, but climate change has elongated dry seasons, increased temperatures, and widened the potential for large-scale wildfires. Beyond weather-related factors, the prevalence of insects like bark beetles damage trees and make them more prone to burning. Invasive vegetation such as cheatgrass also easily burns and contributes to spread.
Trees, traditionally a storage vessel for carbon, release carbon immediately when burning and during decomposition. The EU's Copernicus Atmosphere Monitoring Service estimated that global wildfires in 2022 released 1,455 megatonnes of carbon emissions. Black carbon, or soot, can also travel beyond wildfire zones, absorbing sunlight and warming the earth further.
Beyond the environmental threats, the widening reach of wildfires threatens the displacement of countless residents. Despite this, people continue moving to wildfire-prone areas, putting a growing population at risk of longer fire seasons and associated health risks.
Stacker cited data from the National Interagency Fire Center, National Oceanic and Atmospheric Administration, and the California Department of Forestry and Fire Protection to visualize how the spread of wildfires has worsened in recent years.
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The number of wildfires is decreasing, but more acres are burning
Throughout the mid-20th century, forest management largely focused on preventing forest fires of all scales. Smokey the Bear was a national mascot for fire prevention, overseeing a multi-decade decrease in the number and average size of fires. But without regular fires, debris built up. This, combined with other environmental factors, eventually fueled costlier, large-scale blazes that have come to define the current wildfire season.
Despite having nearly 10,000 fewer fires per year on average from 2011-2021 compared to 1983-2010, the average acreage burned by those fires per year has more than doubled. From 1983-2010, the average number of acres burned per year was about 4.4 million. That number has jumped to 7.5 million acres per year for the 2011-2021 time period.
Wildfire seasons are getting longer
The total acres burned by wildfires in December 2020 was three times greater than the 10-year average for the month. The following year also experienced a damaging December, with a less extensive but still above-average spread covering 336,984 acres. Wildfire season traditionally lasts May through October, but shorter winters and earlier snow melts have extended wildfire risk. 2021 set a record for days at preparedness level 5, the highest alert for wildfire risk.
The USDA Forest Service warned in 2021, "For years, agencies relied on seasonal firefighters for summer months, but now that wildfires are burning into the winter, they need to reevaluate their hiring plans."
Wildfire suppression costs have risen by billions of dollars
With the increasing severity of wildfires every year, it follows that more resources are required to tame the blazes. In 1999, just before the turn of the century, the Forest Service and all other Department of the Interior agencies spent a combined $515.5 million on wildfire suppression. During the course of the last decade, the average cost of wildfire suppression has skyrocketed to nearly $2.1 billion annually. The Forest Service carries the brunt of this cost, contributing approximately three-quarters of the funds each year.
Though there is not currently an official tracking mechanism for the cost of wildfire damages, academics across the country have attempted to estimate the economic impact of wildfires. In 2020, a team of researchers estimated that the 2018 California wildfires caused $148.5 billion in economic damages.
Lightning fires are causing more damage in the West
At the national level, 89% of wildfires were caused by humans in 2022, but human-caused wildfires contributed only to 44% of total acreage burned. In the Southern and Eastern U.S., human-caused fires still cause the most damage, but elongated dry seasons in the West have intensified the impact of lightning when it does strike.
Dry lightning is created through high-altitude thunderstorms. Extreme heat and drought can cause rain to evaporate before it reaches the ground. Lightning fires can also pose greater damage because it can take longer for them to be detected, whereas human-caused fires are often closer to towns and high-traffic areas. Winds associated with dry thunderstorms can further fan the flames as well. These factors mean that even as the West is less prone to lightning than other parts of the country, the bolts can spark more damage.
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California's wildfires continue to set records
While lightning has sparked some of the most devastating fires in California, powerlines have also fueled far-reaching damage. Contact with overgrown trees, downed lines, and frayed wires can spark flames. Pacific Gas & Electric was held responsible for the 2018 Camp Fire and 2019 Kincade Fire and has instituted rolling blackouts on high-risk wildfire days.
Even as the origin of fires varies, each is exacerbated by existing environmental factors. A 2018 survey from the USDA Forest Service identified nearly 150 million trees that died between 2010-2018 in California. Two years later, 2020's record season burned nearly 4.4 million acres, and the five largest megafires happened concurrently in August and September. The season demonstrated how the buildup of vulnerable trees can ignite unprecedented spread.
A 2021 aerial survey by the USDA Forest Service offered some hope. Annual tree mortality declined over a five-year period, with an estimated 9.5 million dead trees in the state spanning more than 1 million acres, although tree mortality remains at a much higher rate than California's pre-drought levels in the early-2000s.
