Petersburg Borough, AK: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Petersburg Borough scores at the 1th percentile for flood hazard, rated "No Rating" — not rated by FEMA’s risk index. The hazard here is split between inland river flooding (about once every 100 years) and coastal storm surge (about once every Infinity years). This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Mandatory flood insurance compliance in Petersburg Borough
FEMA hasn't published a residential structure count for Petersburg Borough's mapped flood zone, so a reliable mandatory-compliance percentage can't be computed here — see the data quality guide for why this gap exists for roughly a quarter of US counties. Looking beyond the mandated zone, 2% of all residential structures in Petersburg Borough carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Petersburg Borough against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Petersburg Borough ranks 3115 — 1 being the highest hazard nationally — and 2927 by population among all 3144 counties covered here, where 1 is the largest. About 3,436 people live in Petersburg Borough, Alaska, spread over 2,900.89 square miles.
Your street may differ from Petersburg Borough's average
Across all of Petersburg Borough's 1,200 residential structures, 24 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Petersburg Borough's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Petersburg Borough's compliance figure is one of the ones affected by FEMA's incomplete denominator data — the data quality guide explains what that means and how many counties it touches.