What will California’s mild fire season mean for 2023?

With consecutive weeks of heavy rain in San Francisco and an early November snowfall in Northern California, many Californians emerged from this year’s wildfire season scratching their heads. Where were the blazing fires that had razed millions of acres of land, turning SF skies orange and ashy? 

California’s fire season looked relatively tame in 2022. Though roughly 7,600 fires have so far ripped through 362,271 acres of land, this year’s degree of damage was tiny compared to years past. 

“Any time we have a below average fire year, we got lucky. The underlying dynamics are just set up for big fires,” said Eric Knapp, a research ecologist with the U.S. Forest Service. 

Experts like Knapp say this year’s fire season was unusual, and certainly welcome after two consecutive record-breaking years of damage, fire and smoke. But many warn that the recent good fortune may not be here to last. Here’s why. 

The past two years have seen some of the worst wildfire seasons in state history: In 2020 alone, over 4.3 million acres of land burned across California, consuming 11,116 buildings and causing over 30 fatalities.  

While this year’s total number of fire incidents (7,592) is on par with the state’s five-year average (7,992), a mere fraction of California land burned in 2022, showing a roughly 85% drop in acres destroyed by fires in the state. 

And it’s not just the number of fires, but the intensity of them that caused a less vicious wildfire season. 

The largest fire of this season, the Mosquito Fire, razed more than 76,000 acres of land. But that statistic pales in comparison to the worst blazes of 2021 and 2020: The 2021 Dixie Fire was more than 10 times as big, and 2020’s August Complex fire wiped out over a million acres of land. 

Notably, PG&E was not responsible for a major blaze in California this year—a change from years’ past, when aging equipment owned by the beleaguered power company was responsible for at least one annual wildfire disaster since 2017. 

Though Californians were breathing a bit easier this fire season, experts warn that 2022’s good fortune is partially just that—luck. And statistics like burned acreage might not tell the whole story. 

“If you look at the number of acres burned, statistics vary hugely from year to year. It's not a linear trend,” Knapp said. 

Take 2019, for example. Following two years of wildfires that devoured millions of acres of land, 2019 reported an uncharacteristically low number of acres burned and a lower-than-average wildfire incident count—much like we saw in this year’s fires. But by the end of the following year, California was once again submerged in smoke, making 2020 its worst, most damaging wildfire season to date. 

So what’s the real reason for wildfire season’s devastating staying power? It’s all in the vegetation, climate and weather. 

“In some ways, you can attribute [big fire seasons] to these conditions, these drought conditions, which are causing larger amounts of dry fuel to be there, be dead and be present,” said Capt. Robert Foxworthy, a public information officer at CalFire. Those underlying conditions, mixed with a lack of rain and maybe a northern wind, means that fires can burn and spread quickly. 

High amounts of dry brush, or “fuel," combined with low rainfall, high temperatures and aggressive winds all contribute to a wildfire’s intensity—and most of those factors were missing in 2022. 

Wildfires that started in January 2022, for example, dissipated quicker and easier than summertime blazes, partially because the fires happened during a time of year when temperatures were lower and precipitation was much more likely. 

Well-timed rainfall in September also helped extinguish the Mosquito Fire, and unusually low winds kept most of the season’s fires at bay. This year also lacked the weather anomalies—such as aggressive lightning—that sparked the most damaging fires of 2020 and 2021. 

“[California was] obviously very dry this year and had hot temperatures. We didn't have a lot of high winds or a red flag warning,” Foxworthy said. “If you remember in years past, a lot of our big fires—look at the 2017 Wine Country fires, for example—were on days with extremely high wind.”

And even though a recent slew of winter storms has brought hefty amounts of rain and snow to Northern California, climate experts say that this unusual level of precipitation is unlikely to result in the end of California’s yearslong drought. 

Rather, the early rainfall signals the start of California’s third consecutive La Niña, in which unusually heavy storms hit early in the winter and then disappear early in the new year, leaving months of cool, dry temperatures. Worst case, this La Niña might extend the drought and dry out the state further, priming California for an aggressive summer fire season. But given the past three years were the state’s driest ever recorded, fingers are crossed for big rains around spring. 

The rare “triple-dip” La Niña is also likely to put a damper on what has been an unusually early and generous ski season: In the Sierras, snowpack levels are at about 200% of the seasonal average, and ski season started early, in November, when a massive snowstorm dumped inches of powder on Tahoe. 

Northern California’s changing climate, as well as a high amount of dry brush across its forests, continue to keep firefighters and scientists on edge, even after a year of relatively tame wildfires and fewer acres burned. 

“We're on the precipice of a big fire season every year,” Knapp said. “Just because last year was a low fire year, don't count on next year being a low fire year.” 

Knapp and other forest ecologists especially point to the overwhelming quantity of brush on California’s forest floors as a cause for ongoing concern. Though the state carries out prescribed burning to reduce this dry forest-floor fuel, experts say the rate of controlled burns pales in comparison with Indigenous fire prevention measures hundreds of years ago—creating fertile grounds for bigger fires that are much more difficult to suppress. 

“The underlying factors that have led to huge fire years in California are still there,” Knapp said. “Our forests tend to be in pretty poor condition. There's way too much fuel on the ground. There's too much fuel continuity. Those conditions can lead to a big fire year.”

Though forest ecologists like Knapp underscore the importance of these prevention efforts, emergency funding for wildfire suppression has steadily risen in the last decade as the state takes a dual-pronged approach to tackle fires.

Foxworthy cites aggressive firefighting efforts around the state as one of the key factors in keeping wildfires at bay. Though California saw nearly 8,000 fires this year alone, the majority are put out by firefighters—and the only ones the public usually remembers are the handful that burn over hundreds of acres. 

“Cal Fire’s strategy is to stop 95% of fires at 10 acres or less. Historically, we're pretty good at that, plus or minus a little bit,” Foxworthy said. 

Lucky for San Franciscans, wildfire season rarely has a direct impact on the city itself. And given the low number of aggressive wildfires this year, the polluting effects and ash from Northern California blazes did not puncture San Francisco’s armor of fog. 

Air quality in the San Francisco-Oakland-Hayward metropolitan area shows that the region did not experience severe pollution due to wildfires this year—so much so that none of the Bay Area air quality stations registered above-standard levels of dangerous fire-produced particulates, called PM 2.5, on a single day in 2022. 

The Bay Area’s worst average PM 2.5 concentration in 2022 just barely brushed 28 µg/m3, well below the state and federal guidelines for good air quality.  

By comparison, air quality in 2020 mirrored the severity of its fire season. Average concentrations of PM 2.5 particles exceeded the federal standard on 125 different days in 2020, producing unhealthy air quality for more than a third of the year. During this time, the worst air quality day in San Francisco saw PM 2.5 levels exceed roughly four times the federal standard and more than six times the city’s worst air quality level in 2022.

Though individual San Franciscans avoided the worst of fire season’s usual smoke and ash, the state’s worsening wildfire problem has devastating long-term impacts on the climate.  

The 2020 wildfire season, for example, eliminated 16 years of the state’s greenhouse gas emission cuts and spouted nearly 130 million megatons of greenhouse gas emissions, according to a UCLA study published in October.  

And even though temperatures have dropped, winter rainfall remains consistent and a blanket of snow has fallen over Northern California, experts warn that some fires in 2020 and 2022 started in December and January. 

Unfortunately, California’s wildfire season has expanded beyond the summertime blazes of the past into a year-round crisis that threatens the land, homes and livelihoods of people across California. 

“Now, we have a large enough state and a large enough variety of ecosystems and fuel types, that somewhere in California we have the ability to have a fire any time of the year,” Foxworthy said.