Overview
On Christmas Eve 2025, Governor Gavin Newsom declared a state of emergency for six California counties as atmospheric rivers dumped torrential rain on ground already saturated from earlier storms. The timing was cruel: burn scars from January's Palisades and Eaton fires—which killed 30 people and torched 37,000 acres—now face catastrophic mudslide risk. Officials evacuated 380 homes and pre-deployed 300 emergency personnel with swiftwater rescue teams.
This is California's new normal. Since December 2022, the state has lurched between climate extremes—nine consecutive atmospheric rivers causing $11 billion in flood damage, followed by devastating wildfire seasons, then floods again. The pattern isn't random: climate change is loading the atmosphere with more moisture while extending drought periods that fuel megafires. When rain finally comes to burned slopes stripped of vegetation, hillsides don't absorb water—they avalanche.
Key Indicators
People Involved
Organizations Involved
Cal OES coordinates California's response to emergencies and disasters, operating 13 swiftwater rescue teams and maintaining pre-positioned equipment statewide.
The USGS program models debris flow risk in burned areas, warning that stripped vegetation creates conditions for catastrophic mudslides.
Timeline
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Atmospheric River Brings Heavy Rain
Climate EventMountains north of LA receive 4-8 inches; one death reported in Northern California flooding.
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380 Homes Evacuated in Burn Zones
EvacuationDoor-to-door orders issued for vulnerable properties in Palisades, Eaton fire scars.
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Newsom Declares Emergency for Six Counties
Government ResponseState of emergency for Los Angeles, Orange, Riverside, San Bernardino, San Diego, Shasta counties.
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Cal OES Pre-Deploys Emergency Resources
Government ResponseState positions 55 fire engines, 10 swiftwater teams, 300+ personnel ahead of atmospheric river.
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Bass Orders Burn Area Fortification
Government ResponseLA mayor issues executive order deploying K-rails, sandbags to prevent debris flows.
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Fires Fully Contained After 30 Deaths
WildfirePalisades Fire killed 12, destroyed 6,837 structures; Eaton Fire killed 18, destroyed 9,414 structures.
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Palisades and Eaton Fires Ignite
WildfireHistoric Santa Ana winds fuel two massive fires that will burn 37,469 acres combined.
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800,000 Lose Power in Southern California
Infrastructure ImpactHigh winds and flooding knock out electricity across multiple counties.
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Back-to-Back Atmospheric Rivers Slam California
Climate EventTwo storms in one week bring record rainfall; downtown LA receives 7.03 inches in two days, third wettest on record.
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Pajaro River Levee Fails
Infrastructure FailureBreach forces evacuation of nearly 2,000 residents in Monterey County.
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Biden Declares Federal Emergency
Government ResponsePresident approves emergency declaration for 17 California counties amid widespread flooding.
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Newsom Declares State of Emergency
Government ResponseGovernor activates emergency protocols as atmospheric rivers intensify statewide.
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First of Nine Atmospheric Rivers Hits California
Climate EventSeries begins that will bring historic flooding through March 2023, killing 22 people and causing up to $11 billion in damage.
Scenarios
Major Debris Flow Kills Dozens in LA Burn Zones
Discussed by: USGS scientists, CalMatters analysis, officials citing 2018 Montecito precedent
The nightmare scenario: sustained rainfall triggers catastrophic debris flows in Palisades and Eaton burn scars, sending boulders and mud through evacuated neighborhoods at 20+ mph. Despite warnings, not all residents leave. Death toll reaches double digits as debris flows hit overnight. Federal disaster declaration follows. The event accelerates California's insurance market collapse as carriers refuse to cover fire-adjacent properties, rendering thousands of homes effectively unsellable. Political pressure mounts for dramatic policy changes on development in fire-prone areas.
Evacuations Work, Minor Damage, Crisis Averted
Discussed by: Cal OES emergency planners, officials highlighting improved preparedness
Pre-positioned resources and early evacuations prevent casualties. K-rails and debris barriers mostly hold. Rainfall remains below catastrophic thresholds or falls in shorter bursts that don't fully saturate slopes. Swiftwater rescue teams execute a handful of rescues but no fatalities occur. Officials tout the success of lessons learned from 2018 Montecito and 2023 atmospheric river disasters. The event becomes a model for disaster preparedness, though it doesn't solve California's underlying climate whiplash problem.
Atmospheric Rivers Intensify, Monthly Pattern Emerges
Discussed by: Stanford researchers, climate scientists, insurance industry analysts
The December 2025 storm is the first of three consecutive atmospheric rivers that pummel California through February 2026, echoing the 2022-23 pattern. Each storm compounds damage as soils remain saturated. Burn zones experience multiple debris flow events. Economic damage exceeds $15 billion. Federal emergency funds run dry. California's insurance crisis deepens as major carriers exit the state entirely. Political battles erupt over managed retreat policies and whether to rebuild in high-risk zones. The crisis forces a reckoning with development patterns established before climate change accelerated.
Historical Context
Montecito Debris Flow After Thomas Fire
January 9, 2018What Happened
Three weeks after the Thomas Fire burned 440 square miles in Ventura and Santa Barbara counties, an atmospheric river dropped half an inch of rain in five minutes on denuded slopes. Debris flows up to 15 feet high roared through Montecito at 20 mph, carrying boulders the size of cars. Twenty-three people died. Over 100 homes were destroyed.
Outcome
Short term: Federal and state emergency declarations; $421 million in recovery costs; 2-year-old victim never recovered.
Long term: Became the template for post-fire debris flow warnings; USGS developed improved modeling; California mandated debris removal protocols.
Why It's Relevant
This disaster haunts current evacuations—officials know exactly what happens when atmospheric rivers hit fresh burn scars, and the death toll is unacceptable.
2022-2023 Nine Atmospheric Rivers
December 31, 2022 - March 25, 2023What Happened
California experienced nine consecutive atmospheric rivers in three months, a historic meteorological event. Levees failed, rivers flooded, 200,000 lost power, and 6,000 were evacuated. Twenty-two people died. Downtown areas became lakes. The Pajaro River levee breach displaced nearly 2,000 residents.
Outcome
Short term: Biden declared federal emergency for 17 counties; California received billions in FEMA aid; economic losses reached $11 billion.
Long term: Forced rethinking of disaster preparedness; Cal OES adopted pre-deployment strategies; insurance crisis accelerated as carriers couldn't price risk.
Why It's Relevant
Established the pattern California now faces—back-to-back atmospheric rivers causing compounding damage because soils can't dry between storms.
Australian Black Summer Fires to Floods
2019-2020What Happened
Australia's worst wildfire season burned 46 million acres and killed 33 people. Months later, torrential rains hit burn scars, causing widespread flooding and erosion. The climate whiplash—from extreme drought fueling megafires to intense precipitation—mirrored California's emerging pattern.
Outcome
Short term: Billions in combined fire and flood damage; ecosystems devastated by compounding disasters.
Long term: Demonstrated that climate change creates cascading disasters where each event worsens the next; influenced Australian development policies.
Why It's Relevant
Shows California isn't alone—climate whiplash between fire and flood is the new reality for Mediterranean climates worldwide.