FEMA's official flood map draws the 1%-annual-chance floodplain. FEMA's National Risk Index adds a comparative flood-risk rating for every census tract — a broader, neighborhood-scale measure. Here's how the tracts in and around Imperial Beach rate, and how to check one address.
| Census tracts intersecting Imperial Beach | 11 |
| … rated Relatively High or Very High for flood (riverine or coastal) | 5 |
That puts parts of the Imperial Beach area among the higher-rated neighborhoods in FEMA's national flood-risk comparison. The National Risk Index rating is a comparative, composite measure (it reflects expected losses and community vulnerability, not just the mapped floodplain), so it complements the official FEMA flood map rather than contradicting it — check a specific address to see the map's call for one property. These are tract-level ratings (neighborhood scale), not parcel-precise and not a count of homes.
| Riverine flood — Relatively High | 5 |
| Coastal flood — Relatively High | 1 |
FEMA rates riverine and coastal flood separately, so one tract can appear in two rows — these rows can therefore add up to more than the 5 elevated tracts above (a tract is "elevated" if either rating is Relatively High or Very High). Categorical classes from FEMA's National Risk Index — never a proprietary score.
City figures are a starting point. To see what the official FEMA flood map will say for one property in Imperial Beach — side by side with these cited federal & state sources — run the free per-address check:
Open the free Beyond-FEMA checker → · See all of San Diego County →
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