Jefferson County, AL: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Jefferson County scores at the 98.1th percentile for flood hazard, rated "Relatively High" — well above the national norm for flood hazard. The hazard here is driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 4.2 times a year. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Jefferson County's flood-insurance compliance gap
13.1% of the homes FEMA requires to carry flood insurance in Jefferson County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 732 policies against 5,592 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 0.5% of all residential structures in Jefferson County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Jefferson County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Jefferson County ranks 66 — 1 being the highest hazard nationally — and 107 by population among all 3144 counties covered here, where 1 is the largest. Jefferson County, Alabama is home to about 664,744 people across 1,111.567 square miles of land.
Your street may differ from Jefferson County's average
1,129 of Jefferson County's 241,933 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where Jefferson County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.