FEMA Records
28
High volume
New Jersey · FEMA + NOAA + National Risk Index
Mercer County, NJ
28 FEMA disaster declarations (1965-2021), with a FEMA National Risk Index rating of Relatively High. Most common hazard: Hurricane.
- 28
- FEMA declarations
- 17
- Major disasters
- 95
- NRI risk · Relatively High
- Hurricane
- Top hazard
The verdict
Mercer County has a nationally busy FEMA history: 28 declarations, more than 81% of counties in this registry. But the state comparison tempers that reading: the total is 6% below the New Jersey county mean. FEMA's separate National Risk Index places the county in the riskiest 5%; that score models loss and vulnerability rather than counting declarations.
- Riskiest 5%
- of U.S. counties for FEMA National Risk Index score
- Relatively High
- FEMA National Risk Index rating
- 28
- FEMA declarations vs 21 national county avg
- 2,430
- NFIP flood insurance claims filed
FEMA's National Risk Index and its declaration registry are separate measures. This county's registry includes Major Disaster (DR) and Emergency (EM) records; an EM authorizes a narrower set of federal assistance than a DR.
How does Mercer County compare?
Mercer County vs. all counties in this dataset
FEMA disaster declarations, all-time
28 Top 19% higher than 81% of 3,266 counties
Each bar is a band; taller bars hold more counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source FEMA Disaster Declarations Summaries v2 · 2026-08-03
Mercer County's FEMA Risk Index score
FEMA National Risk Index composite score vs. the New Jersey county average
Which hazard drives modeled loss here?
FEMA's modeled annual dollar loss for Mercer County is led by Riverine Flooding (about $113.6M Expected Annual Loss, Historical Loss Ratio Relatively High), while Strong Wind carries the highest National Risk Index rating (Very High). EAL and risk score use different inputs; they need not agree.
Source: FEMA National Risk Index (December 2025 release) - Expected Annual Loss vs composite risk rating by hazard.
What does Mercer County's hazard record show?
Reading the federal records together
FEMA's NFIP table contains a substantial paid-claim history for this county: 2,430 claims and $48.4M in payments. PlainHazard labels 500 or more claims a heavy registry record; that is a reporting bucket, not an official FEMA risk grade. The average paid claim was $19.9K. NFIP totals exclude uninsured flood losses and do not measure how many properties currently carry a policy.
Start with the state benchmark: a New Jersey county averages 29.7 federal declaration records, while Mercer County has 28. The gap is 6% below that mean. Fewer entries indicate a quieter history of recorded federal actions, not immunity from a hazard and not a prediction about what happens next.
FEMA National Risk Index
This county sits among the highest-risk counties nationally on FEMA's National Risk Index, a composite score of 95.4/100 (Relatively High). Expected Annual Loss is rated Relatively Moderate (roughly $176.2M in annualized losses). Social vulnerability reads Relatively Moderate and community resilience Relatively High, both critical modifiers of realized harm here. Of the 18 hazards FEMA models, Strong Wind stands out as the sharpest exposure here, rated Very High. FEMA's modeled frequency puts that hazard at an average of 7 times per year here, based on 267 historical events on record.
Declaration frequency
Nationally, Mercer County's 28 FEMA records form a high-volume history; within New Jersey, however, the count is 6% below the county mean. 17 entries carry the Major Disaster classification. The largest incident group is Hurricane, appearing 9 times. The full 56-year record averages 0.5 declarations annually. A DR label alone does not say whether Individual Assistance, Public Assistance, or both followed.
67 /100
Historical Activity Index
High historical activity
Mercer County, NJ · PlainHazard-derived composite from federal records
This 0–100 index is an explicit PlainHazard composite from FEMA declaration history only on the county surface (this DB has no county-level NOAA damage row) . It is not FEMA's National Risk Index, not a forecast, and not a safety, insurance, or preparedness rating. Open the calculator · Methodology
FEMA Declarations (1953–present) High
20/30
28 OpenFEMA declarations, full ingest window (1.4x national county average)
County Disaster Density Moderate
12/25
28 declarations (0.9x state county average of 30)
Major Disaster Share High
15/25
17 of 28 declarations are major disasters (61%)
Hazard Diversity Very High
20/20
8 different disaster types declared in Mercer County
Historical Declaration Activity
Activity Band
High
vs. New Jersey Avg
-6%
State avg: 29.7
vs. National Avg
+35%
National avg: 20.7
Avg Per Year
0.5
Over 56 years
FEMA NRI 8-hazard radar - Mercer County
How to read this radar
Each axis: NRI risk rating (Very Low-Very High) on a 0-100 scale. Rounder = broad exposure; spiky = one or two hazards dominate.
Major Disaster share
61%
Major-heavy
NRI risk score
95
Relatively High
Source: FEMA National Risk Index FEMA National Risk Index Per-county per-hazard ratings, December 2025 release
How often does each hazard strike Mercer County?
FEMA's National Risk Index models a historical event count and an annualized frequency for each hazard type. Most hazards are expressed as modeled occurrences per year; FEMA expresses drought and heat-wave frequency as event-days per year. These modeled frequencies are not forecasts.
| Hazard | NRI Risk Rating | Recurrence |
|---|---|---|
| Strong Wind | Very High | an average of 7 times per year |
| Winter Weather | Very High | an average of 11 times per year |
| Riverine Flooding | Relatively High | an average of 3.6 times per year |
| Ice Storm | Very High | an average of 1.1 times per year |
| Heat Wave | Relatively Moderate | 11 modeled event-days per year |
| Hurricane | Relatively High | roughly once every 9 years |
| Earthquake | Relatively Moderate | roughly once every 532 years |
| Lightning | Relatively High | an average of 34 times per year |
| Cold Wave | Relatively Moderate | roughly once every 1 years |
| Tornado | Relatively Moderate | roughly once every 11 years |
| Wildfire | Relatively Low | roughly once every 1,861 years |
| Drought | Relatively Low | 3.2 modeled event-days per year |
| Coastal Flooding | Relatively Low | an average of 6.2 times per year |
| Landslide | Very Low | roughly once every 15 years |
| Hail | Very Low | an average of 2.4 times per year |
Source: FEMA National Risk Index FEMA National Risk Index Modeled annualized frequency; drought and heat wave use event-days/year, December 2025 release
Disaster Types
Hurricane 9
Severe Storm 7
Snowstorm 4
Biological 2
Drought 2
Flood 2
Fire 1
Other 1
What Hurricane declarations mean here
Hurricane is the most frequent declaration type on Mercer County's federal record, 32% of its declarations. Atlantic tropical systems run on a defined season, 1 June to 30 November, with most activity concentrated between August and October; Pacific and territorial basins run on their own calendars. A single named storm routinely produces one declaration number covering a long corridor of counties at once, well inland as well as on the coast, which is why an affected county's count can jump by several in one year without several separate events having occurred.
One practical distinction matters when reading these records: a tropical declaration usually bundles wind, storm surge and inland rainfall flooding under a single incident, but the insurance behind them is split. Wind damage falls to property insurers, while flood and surge damage is covered only under a separate National Flood Insurance Program policy. That is why a county can show heavy declaration activity and a comparatively small NFIP claims record, or the reverse.
Declaration counts describe past federal action. They are a record of what was declared, not a forecast of future hazard probability.
Declaration Types
What DR / EM / FM mean
FEMA categorizes declarations as Major Disasters (DR), Emergencies (EM), or Fire Management Assistance (FM).
Major Disaster - 17 60.7%
of all 28 declarations
Emergency - 11 39.3%
of all 28 declarations
FEMA Declarations Timeline
| Year | Declarations | |
|---|---|---|
| 2021 | 2 | |
| 2020 | 2 | |
| 2016 | 1 | |
| 2013 | 2 | |
| 2012 | 1 | |
| 2011 | 3 | |
| 2010 | 1 | |
| 2007 | 1 | |
| 2006 | 1 | |
| 2005 | 3 | |
| 2003 | 1 | |
| 2001 | 2 | |
| 1999 | 2 | |
| 1996 | 1 | |
| 1993 | 1 | |
Show 4 earlier declaration years
| 1981 | 1 | |
| 1975 | 1 | |
| 1971 | 1 | |
| 1965 | 1 | |
Disaster Declarations
How the 28 FEMA declarations break into federal action codes (DR / EM / FM). Same DISTINCT grain as the table below.
Download these 28 declarations as CSV . FEMA source data is public domain; our derived presentation is CC0.
| DR# | Title | Type | Incident | Date |
|---|---|---|---|---|
| 4614 | REMNANTS OF HURRICANE IDA | DR | Hurricane | 2021-09-05 |
| 3573 | REMNANTS OF HURRICANE IDA | EM | Hurricane | 2021-09-02 |
| 4488 | COVID-19 PANDEMIC | DR | Biological | 2020-03-25 |
| 3451 | COVID-19 | EM | Biological | 2020-03-13 |
| 4264 | SEVERE WINTER STORM AND SNOWSTORM | DR | Severe Storm | 2016-03-14 |
| 4086 | HURRICANE SANDY | DR | Hurricane | 2012-10-30 |
| 3354 | HURRICANE SANDY | EM | Hurricane | 2012-10-28 |
| 4039 | REMNANTS OF TROPICAL STORM LEE | DR | Severe Storm | 2011-10-14 |
| 4021 | HURRICANE IRENE | DR | Hurricane | 2011-08-31 |
| 3332 | HURRICANE IRENE | EM | Hurricane | 2011-08-27 |
| 1954 | SEVERE WINTER STORM AND SNOWSTORM | DR | Snowstorm | 2011-02-04 |
| 1897 | SEVERE STORMS AND FLOODING | DR | Severe Storm | 2010-04-02 |
| 1694 | SEVERE STORMS AND INLAND AND COASTAL FLOODING | DR | Severe Storm | 2007-04-26 |
| 1653 | SEVERE STORMS AND FLOODING | DR | Severe Storm | 2006-07-07 |
| 3257 | HURRICANE KATRINA EVACUATION | EM | Hurricane | 2005-09-19 |
| 1588 | SEVERE STORMS AND FLOODING | DR | Severe Storm | 2005-04-19 |
| 1563 | SEVERE STORMS AND FLOODING | DR | Severe Storm | 2004-10-01 |
| 3181 | SNOW | EM | Snowstorm | 2003-03-20 |
| 3169 | FIRES AND EXPLOSIONS | EM | Fire | 2001-09-19 |
| 3156 | WEST NILE VIRUS | EM | Other | 2000-11-01 |
Show 8 earlier declaration records
| DR# | Title | Type | Incident | Date |
|---|---|---|---|---|
| 1295 | HURRICANE FLOYD MAJOR DISASTER DECLARATIONS | DR | Hurricane | 1999-09-18 |
| 3148 | HURRICANE FLOYD EMERGENCY DECLARATIONS | EM | Hurricane | 1999-09-17 |
| 1088 | BLIZZARD OF 96 (SEVERE SNOW STORM) | DR | Snowstorm | 1996-01-13 |
| 3106 | SEVERE BLIZZARD | EM | Snowstorm | 1993-03-17 |
| 3083 | WATER SHORTAGE | EM | Drought | 1980-10-19 |
| 477 | HEAVY RAINS, HIGH WINDS, HAIL & TORNADOES | DR | Flood | 1975-07-23 |
| 310 | HEAVY RAINS & FLOODING | DR | Flood | 1971-09-04 |
| 205 | WATER SHORTAGE | DR | Drought | 1965-08-18 |
Storm Events in New Jersey
Statewide NOAA context only. PlainHazard does not currently attribute these state totals to Mercer County.
| Storm Type | Events | Fatalities | Injuries | Property Damage |
|---|---|---|---|---|
| Thunderstorm Wind | 2,853 | 6 | 27 | $33.9M |
| Winter Weather | 1,141 | 8 | 114 | $0 |
| Flash Flood | 955 | 32 | 7 | $226.8M |
| Coastal Flood | 380 | 0 | 0 | $2.0M |
| Winter Storm | 361 | 11 | 8 | $0 |
Source: NOAA Storm Events Database NOAA Storm Events Database State-level aggregated data, 2015-2025
NFIP Flood Insurance Claims
Total Claims
2,430
Total Paid
$48.4M
Avg Per Claim
$19.9K
Source: FEMA National Flood Insurance Program (NFIP) OpenFEMA Claims Data FEMA National Flood Insurance Program (NFIP) OpenFEMA Claims Data
FEMA National Risk Index
Overall Risk
Relatively High
Score: 95.4/100
Expected Annual Loss
Relatively Moderate
$176.2M/year
Social Vulnerability
Relatively Moderate
Community Resilience
Relatively High
Hazard Risk Breakdown
Strong Wind Very High
Winter Weather Very High
Riverine Flooding Relatively High
Ice Storm Very High
Heat Wave Relatively Moderate
Hurricane Relatively High
Earthquake Relatively Moderate
Lightning Relatively High
Cold Wave Relatively Moderate
Tornado Relatively Moderate
Wildfire Relatively Low
Drought Relatively Low
Coastal Flooding Relatively Low
Landslide Very Low
Hail Very Low
Source: FEMA National Risk Index (NRI) FEMA National Risk Index (NRI) Ratings reflect relative scores among all US counties. Data: hazards.fema.gov/nri
The model's sharpest exposure here: Strong Wind
Strong Wind covers damaging non-thunderstorm, non-tornadic wind, the kind produced by steep pressure gradients and downslope events. It is a broad, frequent, low-drama hazard: roofs, signage, power lines and high-profile vehicles, spread across a wide area rather than concentrated on a path.
Worth noting for Mercer County: the model and the federal record do NOT point at the same hazard. Strong Wind carries the highest modeled rating (Very High), while the county's declaration history is led by Hurricane. That is not a contradiction, the two measure genuinely different things. Declarations record federal ACTION, which requires damage costly enough to exceed state and local capacity; the Risk Index models EXPECTED annual loss across all 18 hazards whether or not any declaration ever followed. A hazard can be the county's largest modeled exposure and never once have driven a declaration.
National Risk Index ratings are modeled estimates of expected annual loss, not predictions of what will happen in any given year.
Data-matched county comparisons
Mercer County's closest FEMA peer: Henry County, AL
Comparisons use published FEMA declaration fields plus the National Risk Index composite for Mercer County. Record similarity, not a safety rating.
Closest declaration profiles
Mercer County shows 28 FEMA declarations, led by Hurricane.
Similar Major-disaster share
Mercer County: 17 of 28 of its declarations are Major.
Similar modeled NRI score
Mercer County: NRI composite 95.4 (Relatively High).
How these peers are chosen
Cohort: Published U.S. county equivalents outside the source state or territory. Each metric keeps six ETL candidates; three unique destinations are shown after de-duplicating across axes. Declaration-volume ranking combines count and Major-disaster share and prefers a different leading incident type; Major-share ranks the Major fraction adjusted for volume; NRI ranks the modeled composite score only.
Retained FEMA snapshot feed for Mercer County - capture-dated entries only.
Further reading for this county
Understanding disaster data
Mercer County's NFIP claims file (2,430 claims) and FEMA declaration history measure different federal records - this guide separates them from modeled NRI risk.
More PlainHazard guides
- Most disaster-prone counties - U.S. counties ranked by FEMA declaration totals.
- Understanding disaster data - declarations vs storm events vs NRI scores.
- Preparing for natural disasters - household checklist (not county-specific advice).
Related
Frequently Asked Questions
What is the most common disaster type in Mercer County?
The most common disaster type in Mercer County is Hurricane, with 9 declarations. Other disaster types include Severe Storm (7), Snowstorm (4), Biological (2).
How does Mercer County's FEMA declaration record compare with the New Jersey average?
The typical New Jersey county has 29.7 FEMA declaration records; Mercer County has 28, or 6% fewer. Against the national county mean of 20.7, this county's total is 35% higher. The comparison is historical and says nothing about the probability of a future event.
How many major FEMA disaster declarations has Mercer County received?
Mercer County has received 17 major disaster declarations, representing 61% of all 28 disaster declarations.
How many flood insurance claims has Mercer County filed?
Mercer County has 2,430 National Flood Insurance Program (NFIP) claims totaling $48.4M in payments, with an average of $19.9K per claim.
Does FEMA's top risk-rated hazard match the highest Expected Annual Loss in Mercer County?
No. In Mercer County, Strong Wind has the highest National Risk Index rating (Very High), while Riverine Flooding leads Expected Annual Loss at about $113.6M. FEMA's risk score and dollar-loss model use different inputs, so the leaders often differ.
What was the worst year for disasters in Mercer County?
The most active year for disaster declarations in Mercer County was 2005, with 3 declarations. The county has FEMA disaster data spanning 1965 to 2021.
What is the FEMA National Risk Index score for Mercer County?
According to the FEMA National Risk Index, Mercer County, New Jersey has an overall risk score of 95.4 out of 100 (Relatively High). The county's social vulnerability rating is Relatively Moderate and community resilience is Relatively High. The Expected Annual Loss (EAL) score is Relatively Moderate, representing $176.2M in annualized losses.
Which natural hazard poses the greatest risk to Mercer County?
FEMA's NRI data points to Mercer County as of the latest release is Strong Wind (risk rating: Very High). Other significant hazards include Winter Weather (Very High) and Riverine Flooding (Relatively High). FEMA's modeled event frequency puts strong wind here at an average of 7 times per year, drawn from 267 historical events on record. These scores are based on FEMA's analysis of historical event frequency, exposed assets, and community vulnerability.
Data Sources & Methodology
Disaster declaration data comes from the FEMA OpenFEMA Disaster Declarations Summaries v2 API, which includes all federally declared disasters, emergencies, and fire management assistance grants.
Storm event data is sourced from the NOAA Storm Events Database (2015-2025), which tracks significant weather events including thunderstorms, tornadoes, floods, and winter storms.
Flood insurance data comes from the FEMA National Flood Insurance Program (NFIP) OpenFEMA claims dataset.
This data is provided for informational purposes only. FEMA disaster declarations represent federal response actions and may not capture all local emergencies or weather events.
What this means for Mercer County
Against a New Jersey county mean of 30 declarations, Mercer County, NJ records 28, or 6% fewer. PlainHazard classifies that historical total as high activity.
- Major Disaster is the largest group (17 of 28) in a declaration history that remains below its state benchmark; frequency here is not a forecast. New Jersey overview
- Nationally the county exceeds 81% of recorded county totals, but its own New Jersey benchmark is higher. The ranking keeps those two contexts separate. Most-disaster rankings
- The large NFIP claims file and FEMA declaration history measure different federal records; the guide explains where they overlap and where they do not. Disaster-data guide
A below-average federal record is not a safety guarantee. Use National Weather Service alerts and local emergency-management notices for present conditions, not this historical comparison.
PlainHazard derives this profile from FEMA's Disaster Declarations Summaries and National Risk Index data. The declaration comparison covers 3,266 U.S. counties and county equivalents in this database, refreshed as of 2026-08-03. Read our methodology - how this data is sourced, computed, and verified.
All federal data sources used on this page
- FEMA OpenFEMA, Disaster Declarations Summaries v2 - all federally-declared disasters for this county. fema.gov/openfema/disaster-declarations
- FEMA National Risk Index (NRI) - per-county per-hazard risk ratings and expected annual loss. hazards.fema.gov/nri
- NOAA NCEI Storm Events Database - state-level storm/severe-weather event records, 2015-2025. ncdc.noaa.gov/stormevents
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainHazard Editorial
Verify with FEMA → · Verify with FEMA NRI → · Verify with NOAA →
Every figure on PlainHazard is rendered directly from FEMA federal disaster data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or national statistics report, the data & editorial changelog, or report a data error.