Montana Flood Hazard Profile
Hazard Data · Model Version 2.5
Overview
Montana's flood hazard is dominated by snowmelt timing rather than rainfall alone. Rain-on-snow events in late spring can move a season's runoff through a basin in days, and the 2022 Yellowstone River flooding demonstrated how quickly that can sever access to communities with a single road in. OpenFEMA records 19 flood-related federal declarations for Montana between 1953 and 2025.
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 Montana
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 Montana.
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 Montana address to see location-specific flood hazard scoring with full methodology transparency.
Open Live Map — MontanaData Sources
Related
Monitoring flood exposure in Montana?
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.