Pictures accompanying Professor John Abatzoglou's presentation on the 2025 fire season were blurry. That was intentional, he said, because so much about wildfire is unpredictable.
"There's a lot that we know, and a lot we don't know," he said.
However, Abatzoglou said, some conclusions can be drawn and measures taken to prepare. The management of complex systems professor spoke at a Fire Resilience Seminar hosted by UC Merced on April 17. UC Merced researchers Crystal Kolden and Sandie Ha and the founder of disaster information app Watch Duty, John Mills, also took part.
California has seen a significant increase in wildfires in the last 50 years, Abatzoglou said. "The last decade or so, it's been a bit of a roller coaster." The 2022 and 2023 seasons, for example, were relatively quiet.
Hotter, drier weather, which the Western United States has increasingly seen in the summer months, can exacerbate conditions. And wetter months ahead of those dry, hot days can provide more fuel for fires.
A short series of hot days can change conditions quickly.
"Heat waves are another key ingredient for catalyzing fire," Abatzoglou said. "Half of the burned area in California happened either during or in the three days after a heat event."
This year, a fairly wet winter in northern California will likely slightly delay the start of fire season. Southern California remains in drought conditions, but had a wetter-than-normal March, which might also stave off fires for a while.
"We're probably not going to see anything really interesting right now or over the next few months, but come summer, if we don't get any significant rain events…things could be on," Abatzoglou said.
