Los Alamos County, NM: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Los Alamos County scores at the 11.1th percentile for flood hazard, rated "Very Low" — among the lowest flood hazard in the country. 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 once every 3 years. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Los Alamos County's flood-insurance compliance gap
Out of 3 homes FEMA counts inside Los Alamos County's mapped flood zone, 2 carry the flood policy federal law requires there — 66.7% compliance, short of full coverage. Looking beyond the mandated zone, 0.3% of all residential structures in Los Alamos County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Los Alamos County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Los Alamos County ranks 2813 — 1 being the highest hazard nationally — and 1847 by population among all 3144 counties covered here, where 1 is the largest. Los Alamos County, New Mexico covers 109.123 square miles and counts roughly 19,675 residents.
Your street may differ from Los Alamos County's average
Across all of Los Alamos County's 7,423 residential structures, 19 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Los Alamos 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.