California: Overview

Everything in the main manual and the skill guides applies in California exactly as written. What’s different here is the specific hazard profile and the state, local, and legal context around it. This page is the starting point; the other three pages under California go deeper on laws, local resources, and the data behind the risks named here.

Earthquake risk that sits directly under the state’s two biggest population centers

California’s earthquake risk isn’t a single fault the way the Wasatch Fault or Cascadia are; it’s a dense network of faults, the San Andreas foremost among them, running through or near nearly every major population center in the state. The USGS-led Uniform California Earthquake Rupture Forecast (UCERF3) puts the 30-year probability of at least one magnitude 6.7+ earthquake at 60% for the Los Angeles region and 72% for the San Francisco Bay Area, counting all faults capable of producing one in each area, not just the San Andreas itself.

The USGS’s own ShakeOut planning scenario, built around a magnitude 7.8 rupture of the southern San Andreas, projects roughly 1,800 deaths, 50,000 injuries, and more than $200 billion in losses, with the strongest shaking funneled directly into the Los Angeles basin. Unlike a single-fault risk, this is a standing, structural feature of living almost anywhere in urban California, not a coastal-only or regional concern.

Wildfire risk that’s no longer a future projection

The January 2025 Southern California firestorm, the Palisades and Eaton fires chief among 14 separate destructive fires that month, killed 31 people, burned more than 57,000 acres, and destroyed or damaged over 18,000 structures across the Los Angeles metropolitan area and San Diego County. The Palisades Fire alone is the most destructive fire in the city of Los Angeles’s history. A separate epidemiological study estimated the total mortality impact, counting indirect deaths from smoke exposure and disrupted medical care, at closer to 440; that figure is a statistical estimate, not a confirmed count, and the two numbers measure genuinely different things, direct versus total attributable mortality, not a correction of one by the other.

A third, slower-moving stressor: water

California’s chronic water stress, drought cycles, an aging reservoir and aqueduct system, and a water-rights system genuinely more complicated than most other states’, shapes long-term planning here in a way that doesn’t have a single dramatic case study the way earthquake and fire do, but affects far more of the state, far more continuously. See the Laws page for how California’s water-rights system actually works.

What this means for how you use the rest of this manual

The manual’s Tier structure and the skill guides apply without modification. What’s different in California: earthquake preparedness (Tier 1’s basic supply kit, Tier 2’s extended self-sufficiency) matters across nearly the entire state’s urban population, not a specific fault corridor, and wildfire evacuation planning needs to account for the kind of fast-moving, wind-driven fire behavior the January 2025 fires demonstrated, hours of warning at most, sometimes less.

Sources

• USGS / UCERF3, 30-year earthquake probability for Los Angeles and San Francisco Bay regions: USGS
• USGS ShakeOut Scenario, magnitude 7.8 southern San Andreas planning scenario: shakeout.org
• January 2025 Southern California wildfires, confirmed death toll, acreage, and structure loss; Palisades Fire specific figures: Wikipedia, sourced to contemporary reporting