Lingering energy from Tropical Storm Alberto sparked hundreds of dry lightning strikes across California’s Central Valley on Monday — with almost no measurable rain — igniting several wildfires in the area.
Eastern Fresno County saw the highest concentration of the lightning Monday, with more than 1,000 strikes in just three hours, when at least five brush fires ignited, according to the California Department of Forestry and Fire Protection.
“And we’re expecting more of that today,” National Weather Service meteorologist Emily Wilson said from Hanford on Tuesday.
Dry lightning is hitting desiccated terrain across the San Joaquin Valley and in the Sierra Nevada, she said, where it has the potential to spark additional wildfires in what is already a very active fire year for California, with the total acreage burned so far this year drastically outpacing the five-year average.
“[Plants] cured really fast due to how hot our June was, so our grasses dried out really quickly,” Wilson said. “We might get more dry lightning strikes and that might ignite more grass fires.”
In 2020, a series of summer thunderstorms sparked a lightning siege that led to the state’s worst wildfire year in recorded history, with more than 4 million acres burned.
On Tuesday, there is a 10% to 30% chance of thunderstorms across the eastern San Joaquin Valley and particularly along the Sierra Nevada crest, according to the National Weather Service’s forecast discussion.
The weather service warned that those storms bring the chance of dry lightning and erratic winds, with little rain, which creates dangerous fire conditions. There is also the possibility for thunderstorms along the Central Coast and throughout the Bay Area, where lightning is the greatest concern.
Beware of lightning strikes, especially dry lightning with thunderstorms that produce less than a tenth of an inch of rain. Winds gusting and erratic to 40 mph. #cawxpic.twitter.com/xrsdNJufA7
— NWS Hanford (@NWSHanford) June 25, 2024
Most of those areas will continue to see triple-digit heat through at least Tuesday.
The storms arriving in California this week are remnants of Tropical Storm Alberto that moved northwest after hitting eastern Mexico last week, Wilson said.
“All the moisture had been pretty much rained out, but there was still that energy there,” she added. “Enough energy to produce all that lightning.”
The Bolt and Flash fires ignited Monday afternoon in eastern Fresno County, each growing to about 800 acres as of Tuesday morning, without any confirmed containment, according to Cal Fire. Some nearby communities near Wonder Valley were under evacuation warnings due to the nearby fires.
Slightly south of those two blazes, the Muscat fire started Monday, hitting just over 100 acres by Tuesday morning, also without any containment, according to Cal Fire. Crews also responded to two other small spot fires in the area Monday, which were quickly contained.
The cause of those wildfires are still under investigation, but the National Weather Service said the spate of lightning resulted in a few of Monday’s fire starts.
Wilson urged residents to be on high alert through at least Tuesday evening.
“Because these are dry thunderstorms, they might start up new fires and that’s a big concern for us right now,” Wilson said. “If you hear thunder, there’s probably lightning … go indoors.”