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California Flood Hazard Profile

Hazard Data · Model Version 2.5

Overview

California is exposed to flood hazard from atmospheric river events, winter storms, and post-fire debris flows. The Central Valley, Sacramento-San Joaquin Delta, and coastal urban areas are primary exposure zones. FEMA National Flood Insurance Program data shows California ranks among the top states for repetitive flood loss properties.

In the Historical Record

43
federal disaster declarations (1954–2024)
FEMA OpenFEMA Disaster Declarations
53,171
NFIP flood insurance claims paid
FEMA OpenFEMA NfipClaims, 1978–2024

Counted from the records this platform holds. A figure is shown only where the underlying dataset could be read.

County by County in California

What federal records show has happened in each county: storms, disaster declarations and flood insurance claims. The counties below have the longest NOAA storm records in California.

All California counties

Notable Historical Events

12023 Atmospheric River Sequence — $3B+ total damage across multiple counties
22017 Oroville Dam spillway failure — 188,000 evacuated (FEMA DR-4301)
31997 New Year's flood — $2B+ damage across Northern California

Hazard Scoring Approach

Calchis computes a Calchis Hazard Score (0–10) for flood hazard at any US address. The score is composed of weighted sub-components derived from federal data sources and published research. All score components are transparent and returned in API responses.

These are hazard scores — physical intensity likelihood only. They do not include property exposure or vulnerability data. We never call a hazard score a risk score. See the full methodology for scoring details.

Analyze Your Address

Enter any California address to see location-specific flood hazard scoring with full methodology transparency.

Open Live Map — California

Data Sources

FEMA National Flood Hazard Layerwww.fema.gov
NOAA NWPS River Gaugeswater.noaa.gov
USGS StreamStatsstreamstats.usgs.gov

Related

Monitoring flood exposure in California?

This page is a state-level profile. Calchis scores individual addresses, tracks live flood events against your own locations, and alerts you when one approaches them.

Free includes Live map + 3 triggers + 10 bond positions. Analyst is $149/mo for 1,000-location portfolios, ep curves, predictions, parametric triggers.

Calchis Hazard Score — derived from federal and academic sources listed above. Property exposure data not included. Not a substitute for professional actuarial assessment. Decision-support intelligence — not a primary alerting or dispatch system. Verify against official sources.