The most destructive wildfires in Southern California history. It is the wettest holiday season in the region. The hottest March heat wave on record.
Over the past 15 months, the Southland has seen a series of extreme weather events, and UC climate scientist Daniel Swain says there’s a clear line connecting them all.
“All the extremes we’ve seen in recent years – from extreme heat to extreme dryness to extreme wetness, even serious wildfires – all have clear links to climate change,” he said.
The ongoing heat wave is breaking a number of Southern California heat records, Swain said.
Climate change is warming the atmosphere, raising the base temperature and making greenhouse climates more intense and longer lasting. As a result, we see more frequent and more intense heat waves.
This unseasonably hot March trend is notable not only for its intensity, but also for its timing and scale.
“It goes from Southern California to the Great Plains and from Canada to Mexico,” he said. “I struggle to find more than good, because it’s so extreme.”
It also paves the way for the state to return to a state of drought.
In January, California experienced an absence of abnormally dry areas for the first time in 25 years due to flooding from winter storms, according to the US Drought Monitor. But now, just two months later, a rare drought has returned to parts of Northern California.
A pedestrian crosses Spring Street in Chinatown during heavy rain on Feb. 19.
(Allen J. Schaben / Los Angeles Times)
Despite the dramatic increase in precipitation, Northern California is on track to re-enter drought conditions in the spring, Swain said.
“March is exactly what you don’t want to see if you want to maintain that drought-free state,” he said. “A very hot, very dry month at that time, will take us back in the other direction.”
The potential drought will look different than California’s long-lasting droughts from 2012 to 2016 and 2020 to 2023 — which caused various water use restrictions — because there is still plenty of rain in the state’s lakes following a very wet winter.
“The good news about California’s water infrastructure is that it really takes a multi-year drought that’s really serious to threaten the actual water supply,” Swain said.
Still, the continued dry spell could wreak havoc on California’s agriculture industry and increase the risk of wildfires.
This flurry of weather from heavy rain to extreme heat can be hard for residents to wrap their heads around — but that’s exactly what scientists expect to see more of in Southern California as climate change worsens.
“Sometimes people will say, no, you have to pick one.” It can’t be too wet and too dry,” Swain said, “and that’s not really how the atmosphere works.”
More rain and more drying are “two sides of the same thermodynamic coin,” he explained. This is because warm air draws more moisture from the soil and plants, deepening the drought. At the same time, the warm air holds more water vapor, which is then released in a few, very strong storms.
This pattern can lead to more intense and destructive fire seasons. Heavy rains lead to high growth of grass and brush, which then turns into more fuel during dry spells.
That’s exactly what Southern California went through in preparation for the devastating Palisades and Eaton fires. There were wettest winters in 2022 and 2023, followed by one of the driest periods on record in the fall and winter of 2024.
Hikers walk a trail through the green hills on a hot day in Griffith Park in Los Angeles on Friday.
(Allen J. Schaben / Los Angeles Times)
California is currently still moving enough to be at low risk of wildfires, thanks to recent winter rains; however, the same cannot be said for all Western states during the ongoing historic heat wave.
“I’m looking at satellite images right now as we speak, and I’m starting to see visible flames from wildfires in states like New Mexico and Arizona and Colorado,” Swain said. “Today, it’s the middle of March. That’s amazing.”
It’s too early to tell what the wildfire season will bring to California this year, especially as we enter a potentially significant El Niño event, Swain said.
On the other hand, that brings the possibility of the remnants of the tropical storm to Southern California in the late summer, bringing significant precipitation that can prevent a severe fire season, as happened with the remnants of Tropical Storm Hilary in 2023, he explained.
Or it can lead to dry thunderstorms, and lightning that can ignite many wildfires, as happened in 2020 in Central and Northern California with the remnants of Tropical Storm Fausto.
The only thing that is certain is that California, and the rest of the United States, will continue to see extreme weather conditions in the coming months and years.
