A recent study has determined that significant storms, similar to Hilary, which posed a threat to San Diego three years ago, will become substantially more likely to impact Southern California in the future.
Research from Stanford climate scientists suggests that certain major weather events in the region could occur at least twice as frequently by the end of the century.
Yuan Wang, an assistant professor at Stanford’s Doerr School of Sustainability within the Department of Earth System Science, focuses on the dynamics between the atmosphere and climate change. He explained that August 2023’s storm Hilary, a rare hurricane from the Pacific that weakened to a less fierce tropical storm right before it made landfall near Baja California and San Diego, was regarded as a “hundred-year event” historically.
Now, he categorizes it as more of a “fifty-year event.”
“Currently, a storm like Hilary, which brings heavy summer rainfall, would only occur once every 110 years,” Wang stated. “It’s such an unusual occurrence that many locals struggle to remember the last time a hurricane impacted Southern California.”
“Our calculations show that the return frequency of Hilary-like precipitation will fall to every 50 years by century’s end, primarily due to greenhouse gas buildup in the atmosphere,” he noted.
He emphasized that “this is quite dramatic.”
The team employed advanced methodologies to forecast storm precipitation in the Pacific, including a technique by co-author Kerry Emanuel labeled dynamic downscaling. This approach condenses large-scale atmospheric data into smaller, detailed datasets that utilize synthetic hurricane paths to consider interactions between storms and their local surroundings.
This technique allows for more precise forecasts compared to older methods like statistical downscaling.
“The situation can get quite complex—consider the timing of hurricane-related rainfalls in late summer, a period when we typically experience dryness and are at risk of wildfires,” Wang explained.
The findings relating to tropical cyclone precipitation and potential landslides may raise concerns, but they also present important policy implications for San Diego County and beyond. Fortunately, the area is better prepared than it was a few years ago, according to Tom Corringham, a research economist at the Center for Western Weather and Water Extremes at UC San Diego’s Scripps Institution of Oceanography.
“We need to focus our investments on implementation,” he remarked. “The question is no longer what needs to be done, but how we are going to achieve it.”
Corringham specializes in the economic impacts of extreme weather due to climate change, including financial losses from “hundred-year events.” He stressed that the most critical action is to decrease or eliminate reliance on fossil fuels like oil and gas.
“However, even if we achieve net zero today, we still have to confront the aftermath,” he cautioned. “My priority is addressing climate change while safeguarding those who are most vulnerable.”
Although individual cities and the county have crafted their own action plans, Corringham noted that distinct challenges exist in this region that may not be encountered elsewhere.
“We are a border city—a border region,” he stated. “Furthermore, we have the Kumeyaay tribal nations present as well.”
No community is immune to severe weather events, he added. Even Southern Californians who might escape the effects of fires or floods still feel the repercussions.
“Climate-related disasters truly impact everyone, whether through taxpayer-funded emergency relief or increased insurance costs, it affects us all… By protecting those at the greatest risk, we can alleviate costs for everyone,” he mentioned.
He expressed that while the core premise of the paper regarding the increased frequency of tropical cyclones is intriguing, the unpredictable nature of climate change necessitates proactive measures to save regions both money and resources in the long run.
“Those most affected by these challenges have contributed the least to the problem,” Corringham pointed out. “There is a strong equity and justice aspect to climate action that is taken seriously both globally and locally… Typically, those with fewer resources are the least resilient to the impacts of climate change, which is why we need policies that protect the most vulnerable.”
“Ultimately, these policies will be the most effective at reducing costs for our communities,” both in economic and equitable terms, he asserted.
This initiative mirrors California’s evolving approach, as seen in the launch of ReCoverCA, a new statewide program aimed at assisting homeowners in recovery following natural disasters. This program supports eligible residents in repairing or rebuilding homes damaged by severe storms from February to July 2023 and January 2024.
This program specifically targets residents in San Diego impacted by significant weather events on January 22, 2026, which led to flooding in regions like Southcrest and Mountain View.
“This program is all about rebuilding better—our goal is not just to restore what was lost but to improve upon it,” stated Maziar Movassaghi, assistant deputy director for Disaster Recovery at the California Department of Housing & Community Development.
“(We want to) enhance community resilience, which is why we strongly encourage residents to apply.”
Throughout July, the state will be present at the Malcolm X Branch Library to provide ongoing support for San Diegans interested in applying for the program.
