Lightning Strikes Cause Brush Fires in California This Week, New Study Says This Will Increase

Over a dozen lightning strikes have caused brush fires throughout California this week.

A series of dry thunderstorms, meaning a storm with lightning and little to no rain, roared from the southwest desert area on Tuesday bringing over a thousand lighting strikes during increased temperatures.

The National Weather Service (NWS) reported numerous fires appeared to have been ignited due to extreme lightning in southeast Monterey County and southwest Fresno County around 3:00 a.m. Tuesday.

NWS also stated that within a five and a half hour window, they counted approximately 4,800 total lightning strikes including in-cloud and cloud-to-ground lightning between the inland East Bay of San Francisco and the California Central Valley.

Shortly after the thunderstorms. the California Department of Forestry and Fire Protection (Cal Fire) reported over a dozen new wildfires. From early Tuesday into Wednesday morning, Cal Fire reported 45 new fires in their jurisdiction.

@abc7newsbayarea CAL FIRE says there have been nearly 17,000 lightning strikes in the last 24 hours in California, starting 80 new fires (most have been small).Currently, there are 33 active fire incidents throughout California. Nine of those fires are burning in Tuolumne/Calaveras Counties and are now known as the TCU September Lightning Complex.In August, there were over 110,000 lightning strikes that caused 534 fires across California. #lightning #lightningstrikes #ca #wildfires #fire #fyp #news #foryoupage ♬ original sound – ABC7 News

In Southern California there were various advisories from the NWS ranging from “Special Weather Statements” to the possibility for flood and thunderstorm advisories. This was in conjunction with already increased temperatures and heat warnings.

Southern California Edison also responded to the weather advisories by issues Public Safety Power Shutoff (PSPS) warnings for various areas due to increased risk of fires. 

Researchers at UC Merced warn that climate change is likely to bring an increase in both cloud-to-ground lightning and the risk of lightning-caused wildfires, according to their latest paper.

Lead author Dmitri Kalashnikov said his projections show an increase in cloud-to-ground lightning over the next three decades or so, particularly in the interior northwestern United States and northern Rocky Mountains.

“Lightning is a big wild card when it comes to the outcome of fire seasons here in California and other parts of the Western U.S.,” said co-author John Abatzoglou, a climatologist and management of complex systems professor at UC Merced. “Some of the biggest fire seasons — like 2020 — really got going due to widespread lightning outbreaks in summer.”

The study highlights the critical need to manage forests and prepare vulnerable communities as wildfires intensify due to a warming planet, while addressing the limitations of global climate models in directly simulating future lightning. Using a machine-learning technique called convolutional neural networks, researchers were able to predict future lightning patterns over the western U.S. by analyzing meteorological conditions simulated by climate models.

This advanced approach provides the most detailed projections to date of lightning activity and its impact on wildfire risk in the region.

“There are already a lot of studies that say future wildfire activity will increase in the Western U.S. and that’s without even considering the potential of increased lightning, which we’re showing is going to happen in many areas,” Kalashnikov said. “Our study makes projections of increased lightning and fire risk for the relatively near future — 2031 to 2060 — whereas other studies tend to make projections for later in the 21st century. This should carry additional relevance for near-term planning and policy decisions.”

Researchers predict an increased likelihood of cloud-to-ground lightning on days with meteorological conditions favorable for wildfires, raising the risk of lightning-ignited blazes. These findings are critical for understanding shifts in wildfire risk and planning fire management strategies in a warming climate.

While prior studies have suggested an increase in lightning activity under future climate conditions, there has been limited research specifically addressing dry lightning in the western United States. This study fills that gap, providing valuable insights into how lightning patterns may evolve and contribute to fire danger.

However, an increase in lightning activity does not directly translate to fire risk, as other factors like temperature, rainfall, wind, and vegetation dryness also play a role. In regions like the Rockies, the days with a high likelihood of lightning-caused fires are expected to increase by three or more by mid-century, even though the overall surge in lightning activity will be larger.

Meanwhile, areas like Utah and Arizona may see fewer lightning days but higher wildfire risk due to drier conditions. Similarly, much of the Southwest is projected to experience fewer increases—or even declines—in lightning activity, yet an uptick in lightning-triggered wildfires remains a concern given the region’s heightened vulnerability to wildfire conditions.