October in California is typically known as a dangerous moment in peak fire season, the month when the state has seen some of its most destructive wildfires, but an early-season storm that swept from the Bay Area to Los Angeles this week has lessened the risk that wildfires will spark, according to state fire meteorologists and other experts.
The storm, which the National Weather Service described as rare for this time of year, dropped as much as four inches of rain in some parts of the state. That has likely curbed the threat of large wildfires in the north through the end of the year and into winter, particularly if more rain falls soon, according to Brent Wachter, a fire meteorologist with the U.S. Forest Service in Redding, Calif.
In Southern California, the fire threat has been reduced significantly for the coming weeks, but experts warned that because the region is in a drought, if the weather turns warm and dry again, and the Santa Ana winds return as they often do in late fall, the risk of fires there may return.
“I wasn’t expecting a big storm to hit this early,” said Matt Shameson, a fire meteorologist with the U.S. Forest Service in Riverside, Calif. “Usually we don’t see anything like this until end of November, even until end of December. Last year, we didn’t have significant rainfall until the middle February.”
California started the year with wildfires whipping through Los Angeles neighborhoods in one of the most expensive and deadly disasters in the state’s history. By the time peak fire season bore down in late June, with vegetation drying out and temperatures expected to rise, experts were warning the state could have an especially brutal summer for wildfires.
Instead, the summer — typically California’s most intense period for wildfires — was relatively subdued, especially when compared with summers in the last decade when hundreds of thousands, even millions, of acres burned. While thousands of fires ignited and dozens of structures burned over the summer, only a scant number of fires grew into large, destructive conflagrations.
“California was quiet,” said Craig Clements, director of the Wildfire Interdisciplinary Research Center at San Jose State University. “We lucked out.”
A similar story unfolded across much of the Western United States, with low to average wildfire activity, though several states had at least one explosive fire that spurred evacuations and destroyed homes. In Colorado, the 137,000-acre Lee fire was among the largest ever in the state, while the Dragon Bravo Fire in Arizona, the largest wildfire in the country so far this year, charred 145,000 acres and a historic lodge in Grand Canyon National Park.
Conditions were more extreme in Canada, which endured its second-worst summer wildfire season on record, according to the Canadian Interagency Forest Fire Center. The season there started early in May and persisted through the summer with hot weather and dry air masses, leaving the vegetation parched and flammable. The province of Saskatchewan was the hardest hit, with seven million acres burned.
The destruction in Saskatchewan alone “is close to what we would have considered our annual national average a few years ago,” said Richard Carr, a fire research analyst with the Canadian Forest Service.
Amid a changing climate, wildfires have gone from a seasonal threat to a year-round hazard across the West, and particularly in California. Still, the state’s largest forest fires usually occur during the peak season, July through October.
This year, only one fire, the Gifford fire in the coastal mountains of Central California, grew into a megafire, generally defined as a fire of at least 100,000 acres. A cluster of fires ignited by lightning in the Sierra Nevada foothills became the season’s most destructive blaze, tearing through the historic gold rush town of Chinese Camp and destroying 95 structures.
Thousands of wildfires ignited this summer in California, but the total acreage burned this year is trending below normal. Cal Fire, the state’s firefighting agency, reports that since 1987, fires have burned on average about 800,000 acres a year, including some significant outliers such as 2020, when 4.3 million acres burned. This year, about 522,000 acres have burned since Jan. 1, including the 37,000 acres from the Palisades and Eaton fires in Los Angeles County, two of the state’s deadliest and most destructive wildfires in history.
This year, forecasters had predicted that prolonged heat waves would dry out the landscape and increase the risk of fire in the fall and summer. While there were a few spells of hot weather and temperatures trended above normal across many inland areas, the record-breaking heat never materialized.
“You look at the number of 100-degree days we had this year and it’s significantly lower than some past years,” said Jesse Torres, a spokesman for Cal Fire.
“We did not have those heat waves,” said John Abatzoglou, a climatologist at the University of California, Merced. “We just did not.”
Coastal areas recorded below-average temperatures throughout much of the summer, and July was cooler than normal across the state.
The heat did not come, but another weather pattern that increases wildfire risk did: lightning. In California, summer thunderstorms are often dry, and lightning strikes can easily spark big fires in the absence of rain. This summer there were an unusually high number of lightning events, but many of these were accompanied by rains — which ultimately reduced the fire risk.
“Lightning can really change the course of a fire season,” Mr. Abatzoglou said. But it “didn’t strike a landscape that was as dry as previous years,” he added.
Amy Graff is a Times reporter covering weather, wildfires and earthquakes.
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