Washington Flood Hazard Profile
Hazard Data · Model Version 2.5
Overview
Washington experiences riverine flooding from atmospheric river events and snowmelt, particularly in the Skagit, Nooksack, and Chehalis river valleys. Urban flooding affects the Puget Sound metro area. Lahar hazard from Mount Rainier represents a unique volcanic-flood compound risk for the Puyallup and Nisqually valleys.
In the Historical Record
Counted from the records this platform holds. A figure is shown only where the underlying dataset could be read.
County by County in Washington
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 Washington.
Notable Historical Events
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 Washington address to see location-specific flood hazard scoring with full methodology transparency.
Open Live Map — WashingtonData Sources
Related
Monitoring flood exposure in Washington?
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.
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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.