51,523 flood insurance claims·$2.3B paid·11 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Nassau County, New York. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Flash flooding from heavy rainfall and thunderstorms dominates the flood profile of Nassau County, accounting for the majority of local flood events over the last 30 years alongside coastal flooding, general floods, tropical storms, and storm surges. NOAA storm records document severe events such as a slow-moving frontal boundary on July 31, 2025, that caused stranded vehicles and multiple road closures, as well as a large low-pressure system on January 10, 2024, that produced record-level precipitable water values and 2 to 4 inches of rainfall.
NFIP historical claims data indicates that flood risks extend well beyond designated high-risk areas. Properties in Zone A have recorded 35,667 claims with an average water depth of 12 inches and an average payout of $52,490. Meanwhile, properties in Zone X have experienced 11,538 claims with an average water depth of 7 inches and an average payout of $51,620. Shaded and unshaded Zone X areas account for thousands of additional claims with average recorded water depths of 4 to 5 inches.
Homeowners, real estate agents, and journalists should pay the closest attention to properties located in Zone A due to the high frequency and depth of flooding, while also noting that properties categorized under Zone X face substantial risk and historical claims from heavy precipitation and localized flash floods.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
8% of Nassau County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
38,970 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 10 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2012, with 27,136 claims and $2.0B paid, the year of Hurricane Sandy.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
104 NOAA storm reports from Nassau County describe what happened, in the words of the forecasters who covered it. Read the New York flood stories →
31 federal disaster declarations since 1965, 11 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storm And Flooding | Sep 28, 2023 |
| Remnants Of Hurricane Ida | Sep 1, 2021 |
| Hurricane Henri | Aug 21, 2021 |
| Tropical Storm Isaias | Aug 4, 2020 |
| Hurricane Sandy | Oct 27, 2012 |
| Hurricane Irene | Aug 26, 2011 |
| Severe Winter Storm And Snowstorm | Dec 26, 2010 |
| Severe Storms And Flooding | Mar 13, 2010 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
263 since 1996: 169 flash floods, 21 river or area floods and 67 coastal floods or surges.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jul 31, 2025 | — |
| Flash Flood | Aug 18, 2024 | — |
| Coastal Flood | Jan 13, 2024 | — |
| Coastal Flood | Jan 10, 2024 | — |
| Flash Flood | Jan 10, 2024 | — |
| Flash Flood | Jan 9, 2024 | — |
| Flash Flood | Aug 6, 2024 | — |
| Flash Flood | Sep 29, 2023 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jul 31, 2025. A slow moving frontal boundary moved over the local area triggering heavy rainfall and thunderstorms across NJ and NYC causing flash flooding across the area resulting in vehicles being stranded and multiple road closures.
Flash Flood · Aug 18, 2024. A frontal system over the area on August 18th and into the early morning hours of August 19th allowed for the development of multiple rounds of slow moving heavy thunderstorms which resulted in widespread significant to catastrophic flash flooding for portions of Southeast New York, specifically for the north shore of Long Island. Several rounds of rain moved through during the day on August 18th. By the afternoon…
Coastal Flood · Jan 13, 2024. Strong low pressure shifted northeast through the eastern Great Lakes on January 13, 2024, sending a warm front through during the morning hours, followed quickly by a cold front. Strong winds produced by this system, combined with peaking high astronomical tides associated with a recent new moon, produced widespread moderate to major coastal flooding along the entire southeast New York coastline and along the Low…
Coastal Flood · Jan 10, 2024. Strong low pressure moving northeast from the Mid Atlantic region to southern New England during the night of January 9, 2024 into the early morning hours of January 10, 2024 produced high winds, which combined with high astronomical tides associated with an upcoming new moon to produce widespread moderate to major coastal flooding along the south shore of Long Island and along the Hudson River in Southeast New York.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Nassau County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.