Why California and the West could face a ‘big fire season’ later this year

As California continues to recover from devastating January wildfires and extreme dryness that reached deep into winter, there are early signs that the state and surrounding region could face a troubling fire season in the months ahead.

The rainy season in the West is winding down, but much of the region remains well behind on rainfall. The Southwest is in deep drought after largely missing out on storms this winter. Much of the broader West is forecast to have unusually hot and dry weather in the coming weeks and months. And that heat – along with the recent proliferation of additional fire-fueling vegetation – could accelerate the turnaround into yet another wildfire season, with high risks of concerning conflagrations even for areas that had adequate rain and snow this winter.

California’s fire season typically starts up in May as grasses dry out, and this year could see heightened wildfire risk by June that becomes widespread in July, according to outlooks released at the beginning of this month.

“I expect it to be a big fire season,” said Matt Shameson, a meteorologist with the U.S. Forest Service in Riverside. “We have a lot of fuels out there in every category.”

And conditions are already emerging that could speed up that process. A heat wave is building this week, with record-breaking temperatures possible in parts of California and the Southwest.

How heat and dry conditions spell trouble for fires

Recent seasonal outlooks show abnormally warm and dry conditions centered over the Southwest this spring and expanding over much of the West into the summer.

There are several ingredients at play, including lingering impacts from a weakening La Niña, which typically promotes dry conditions for Southern California and the Southwest. When drought conditions are prominent, they can also supercharge heat waves – a result of positive feedback with the dry land surface. Long-term warming trends have also made scorching heat more likely.

The warmth could trigger rapid snowmelt along with earlier or more intense wildfires.

During a late-March heat wave, mountain snow saw a notable melt event across much of the region, even at higher elevations.

A shift toward cooler or wetter conditions is still possible, though the window for Pacific storms is closing and a dry spell looks likely for much of April.

Johnna Infanti, a meteorologist with the National Weather Service’s Climate Prediction Center, said the current outlook doesn’t preclude the possibility of late-season storm events – which could at least partially help with any fire risk.

Southern California

After starting the year with devastating and historic fires, storms in February and March in this part of the state finally turned hillsides green and moistened plants, halting wildfire concerns at least temporarily.

But the southern half of the state remains in moderate-to-extreme drought.

Well-timed rains in March were just enough to sprout and grow a knee-high grass crop. When fires spark this summer and fall, these are the grasses that can carry and spread the flames into drought-stressed brush. That will add to the fuel of the previous two wet winters – the 2022-2023 and 2023-2024 seasons – which saw an explosion of grasses four to six feet tall along with dense growth of flammable brush.

April is a critical month for precipitation and will determine not only how much vegetation will grow but when it will die off and become fuel for fires, said Leslie Roche, a professor of plant science at the University of California at Davis.

If rains stop falling, that will trigger these annual grasses to “grow quickly, set seed out and die,” Roche said. “All of that dry fuel – like we just saw in Southern California – has disproportionately strong impacts on wildfire severity and spread.”

Pacific Northwest

Early forecasts also suggest a higher summer wildfire risk for the northern third of California, which had a wet winter and where snowpack and reservoirs have fared well for a third straight year.

If the predicted warmth materializes, snowpack could melt off early and there could be a “quick transition towards an unusually flammable fuel bed” in June and July, according to the latest wildfire outlook.

It’s a similar picture for the Pacific Northwest, which has been battered by spring storms and even flooding – yet could still see a busy fire season.

Roche worries about temperature spikes that can create thirsty conditions – the whiplash that is a signature of climate change that is driving worsening wildfires.