Trempealeau County, WI: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Trempealeau County scores at the 67.5th percentile for flood hazard, rated "Relatively Low" — below 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 2.8 times a year. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Mandatory flood insurance compliance in Trempealeau County
Out of 649 homes FEMA counts inside Trempealeau County's mapped flood zone, 55 carry the flood policy federal law requires there — 8.5% compliance, short of full coverage. Looking beyond the mandated zone, 0.6% of all residential structures in Trempealeau County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Trempealeau County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Trempealeau County ranks 1067 — 1 being the highest hazard nationally — and 1421 by population among all 3144 counties covered here, where 1 is the largest. Trempealeau County, Wisconsin covers 732.966 square miles and counts roughly 30,801 residents.
Your street may differ from Trempealeau County's average
Across all of Trempealeau County's 10,234 residential structures, 61 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Trempealeau 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.