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Beneath the Surface of California’s “Thousand-Year” Storms

Updated: Feb 22

This month's storms in Southern California, characterized by heavy rainfall and severe flooding, have garnered national attention.


Governor Gavin Newsom declared a state of emergency for “thousand-year” storms, or storms with a 0.1% chance of occurring within a given year. With this being the second “thousand-year” storm that Southern California has seen in the past three months, storms of this strength are only increasing in frequency.


The science hasn’t lied: climate change is causing us to see weather patterns in our region become rapidly more extreme, making natural disasters, like storms and flooding, more likely to occur.


We’re experiencing the tail end of El Niño, one phase in the El Niño Southern Oscillation (ENSO) Cycle. The El Niño phase, which describes the warming of temperatures, is frequently associated with floods and weather disturbances. California’s history with El Niño-related floods includes storms in 1982 and 1997 that led to significant flooding and over $1.4 billion in damages.



Rising global temperatures due to increased carbon emissions intensify cycles like the water and ENSO cycles. Warmer air holds more moisture, and we’re seeing that lead to more intense and prolonged rainfall in certain regions.


With continued global warming, increasing sea levels, and extreme weather, flood-prone regions nationwide are projected to expand by nearly 50%. We must focus on mitigation and adaptation to increase our resilience in the face of our changing climate.


We must stop climate change at its source, greenhouse gas emissions. The Intergovernmental Panel on Climate Change (IPCC) reports the frequency of heavy rainfall events in many regions, including Southern California, has increased due to human activity. We’re working to stop the climate crisis by advocating for 100% clean energy, walkable bikeable neighborhoods, world-class transit, shade trees, and all-electric buildings.


Additionally, we need to adapt by focusing on long-term solutions, like investing in our stormwater systems and green, resilient infrastructure, strengthening our water management strategies, and improving urban planning through a lens of equity and sustainability. We must now act together as a region to safeguard our communities and minimize economic loss and damage.


We're advocating for our leaders to acknowledge the severity of the climate crisis and fighting for long-term solutions, including investments in stormwater systems and into frontline communities hit first and worst by the climate crisis.


➡️ Read 'The Cost of California's "Thousand-Year" Storms: San Diego After the Floods' to learn more about our recent storms' economic and social impacts.


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