A recent surge in California fire activity, punctuated by a large blaze that erupted outside of San Francisco on Saturday, has officials wondering if this year’s fire season could be worse than expected. The forecast is complicated, however, by a mix of competing factors both increasing and decreasing the fire risk.
With plenty of thick grasses as fuel, the fire season is off to a much faster start than last year. Several fires are burning across the state, and an impending heat wave in the West could further increase the risk of flames. Experts, though, still favor the latter part of the fire season, which typically runs from April to October, to be the worst.
The fire that broke out over the weekend, named the Corral Fire, was reported to be 90 percent contained as of Tuesday morning after burning more than 14,000 acres in San Joaquin County just south of Tracy, Calif. The cause of the fire, located about 60 miles east of San Francisco, is still under investigation.
California’s fire season has become more active in the past two weeks as warm, dry weather that took hold in May has dried out thick grasses that sprouted during the previous two wet winters. Once a fire is sparked, gusty winds can quickly spread the flames across dry grasses.
Cal Fire listed eight active fires as of Tuesday morning. While much of the activity is in the central and southern portion of the state, the Corral Fire in Northern California is by far the state’s largest fire this year. Driven by gusty winds, that fire burned down a home, injured two firefighters and forced thousands to evacuate, the Associated Press reported.
Wildfires have now burned more than 34,000 acres in the state this year, well past the 8,500 acres that have typically burned by early June and the 2,500 acres that had burned at this time last year.
For now, the fire risk is mainly confined to grasslands during windy conditions. How flammable the rest of the state gets depends on heat and moisture trends this summer. A heat wave expected across much of the state late this week and into the weekend, which is forecast to send temperatures in central California to near and above 100 degrees, will further decrease snowpack and dry out vegetation.
An uncertain forecast
There are mixed signals for how this year’s wildfire season will play out.
Back in early May, forecasters were anticipating a lower fire risk toward the early part of the summer after California received plenty of rain and snow during the winter and spring, although predictions of a hot summer and a delayed or weak southwest monsoon were already raising concerns for later in the season.
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While unexpected, the recent uptick in fire activity hasn’t necessarily changed the forecast going forward, as forecasters are still balancing competing factors.
On the one hand drought, which increases fire risk, is not currently a major concern after a second-straight stormy winter. Even though the recent warmth has dwindled the state’s snowpack to 44 percent below normal, reservoir levels remain 18 percent above normal after slightly above-average precipitation for the year to date.
“I am not expecting drought at least through the next few months,” said Brent Wachter, a fire meteorologist at the National Weather Service.
On the other hand, abundant vegetation could provide plenty of fuel for fires, as the Corral Fire and others have already shown, especially if combined with dry, hot weather. The Weather Service’s outlook for June, July and August favors above-normal temperatures across the state.
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“We have lots of extra fuel with two wet years in a row, so August could become active, especially if we get the expected warmer-than-normal month of July,” said Alex Tardy, a meteorologist at the National Weather Service in San Diego. “We are also looking at less monsoon activity for the West, so combined with repeated heat waves … August to October could be quite active.”
Still, there is plenty of uncertainty in the forecast, with the ongoing fires perhaps throwing forecasters another curveball.
“One way to think about early season grass fires is that the burned area represents one less patch of land that can potentially burn later in fire season, when conditions are far drier and fire crews less readily available,” Daniel Swain, a climate scientist at UCLA, said on X.
Diana Leonard contributed to this report.
