How much flood risk does Roberts County actually carry?
Roberts County lands at the 38th percentile of FEMA's National Risk Index for flooding, "Relatively Low" territory — below the national norm for flood hazard — with the hazard driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 1.3 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 Roberts County
4.6% of the homes FEMA requires to carry flood insurance in Roberts County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 13 policies against 286 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Roberts County, not just the ones FEMA mandates, 0.5% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Roberts County against the rest of the country
Roberts County sits at rank 2014 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 2390 of 3144 by population (1 is biggest). Roberts County, South Dakota covers 1,101.055 square miles and counts roughly 10,283 residents.
Checking a specific address in Roberts County
Across all of Roberts County's 5,141 residential structures, 25 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Roberts County's numbers. The guide to what the Special Flood Hazard Area actually means explains why the mandatory-insurance rule exists and who it applies to.