Mercer County, New Jersey
County storm and disaster record · FIPS 34021 · population 386,483 · 224 sq mi
NOAA's Storm Events Database holds 1,167 records for Mercer County, New Jersey from 1950 through June 30, 2026, on 886 days; the most frequent are severe thunderstorm wind events (275 records). 624 of them are forecast-zone records, which the National Weather Service files once per zone: a county covered by several zones receives each one, so a single storm can add several records on the same day. The deadliest single record is the October 29, 2012 high wind, filed for the forecast zone Mercer, which covers the county: 3 deaths and $129 million in damage in 2025 dollars. FEMA has issued 28 declarations naming the county since 1965, 25 of them for natural hazards; the latest for a natural hazard was “Remnants of Hurricane Ida” on September 5, 2021.
The record, 1950 to 2026
Storm records filed for the county each year (2026 to June 30, 2026). Before 1996 NOAA recorded only tornadoes (from 1950), thunderstorm wind and hail (from 1955).
- recorded, no damage figure
- under $100,000
- $100,000 or more
- $1 million or more
- $10 million or more, or a death
- $100 million or more, or 10 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- 1955: wind and hail recorded from 1955
- 1996: all 48 event types from 1996
- Storm records
- 1,167on 886 days, 1950 to June 30, 2026
- Deaths recorded
- 14136 injuries
- Damage, 2025 dollars
- $426Mas filed (scale steps before 1993)
- Tornadoes
- 18strongest EF2
- FEMA declarations
- 28latest 2021
Source: NOAA NCEI Storm Events Database, records through June 30, 2026 (file revision 20260918); damage converted to 2025 dollars with the BLS CPI-U. Search the record at NCEI. BLS consumer price index.
What hazards hit Mercer County most?
The most frequent records are severe thunderstorm wind events: 275 since 1955. 52% of its severe thunderstorm wind events since 1955 fell in June and July. The rank column places the county among New Jersey's counties by days with a record per 1,000 square miles of land over each hazard's complete period.
| Hazard | Records | Days | First, last | Killed | Injured | Damage | Rank in state |
|---|---|---|---|---|---|---|---|
| Severe thunderstorm wind | 275 | 182 | 1955-2026 | 0 | 8 | $3.5M | 3 of 20 |
| Winter storms | 225 | 223 | 1996-2026 | 1 | 79 | $5.2M | 1 of 20 |
| Floods | 137 | 114 | 1996-2026 | 4 | 6 | $265M | 8 of 20 |
| High wind and dust storms | 128 | 126 | 1996-2025 | 4 | 15 | $135M | 3 of 20 |
| Heat | 92 | 92 | 1996-2025 | 5 | 19 | – | 2 of 20 |
| Hail | 63 | 40 | 1974-2023 | 0 | 0 | – | 5 of 20 |
| Fog, smoke and funnel clouds | 53 | 51 | 1999-2026 | 0 | 0 | – | 1 of 20 |
| Heavy rain | 52 | 47 | 1996-2022 | 0 | 0 | – | 3 of 20 |
| Drought | 44 | 44 | 1997-2015 | 0 | 0 | – | 1 of 20 |
| Lightning | 38 | 32 | 1997-2020 | 0 | 8 | $2.4M | 3 of 20 |
| Extreme cold | 31 | 30 | 1996-2022 | 0 | 0 | – | 2 of 20 |
| Tornadoes | 18 | 16 | 1958-2024 | 0 | 1 | $14M | 2 of 20 |
| Wildfires | 6 | 6 | 2001-2012 | 0 | 0 | – | 5 of 20 |
| Hurricanes and tropical storms | 3 | 3 | 2008-2020 | 0 | 0 | $656K | 14 of 20 |
| Rip currents and high surf | 2 | 2 | 2016-2016 | 0 | 0 | – | 12 of 20 |
Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.
How many tornadoes has Mercer County had?
NOAA records 18 tornadoes in Mercer County from 1958 to 2024, the strongest rated EF2, with 0 deaths and 1 injury recorded in the county. That is 2nd of 20 New Jersey counties and 175th of 3,080 U.S. counties by days with tornadoes per 1,000 square miles since 1950. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.
Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 17 tornadoes whose track touched Mercer County since 1950 (NOAA's county records number 18: they file a crossing tornado once per county segment, and the two databases differ on some tracks); along their whole tracks they killed 0 people.
| Date | Tornado | Rating | Path | Killed |
|---|---|---|---|---|
| 1960-06-24 17:00, as SPC files it | Hightstown | F3 | 12.9 mi | 0 |
Map of the strongest tornado tracks in New Jersey.
Every tornado record filed for Mercer County (18)
| Date | Place | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2024-06-14 | Slackwood, Mercer County | EF0 0.13 mi x 60 yd | 0 | 0 | – |
| 2023-04-01 | North Crosswicks, Mercer County | EF1 1.81 mi x 300 yd | 0 | 0 | – |
| 2023-04-01 | North Crosswicks, Mercer County | EF1 0.06 mi x 300 yd | 0 | 0 | – |
| 2023-02-21 | Lewisville, Mercer County | EF2 5.8 mi x 200 yd | 0 | 0 | – |
| 2021-09-01 | Clarksville, Mercer County | EF0 2.61 mi x 100 yd | 0 | 0 | – |
| 2021-07-29 | Robbinsville Airport, Mercer County | EF1 1.64 mi x 100 yd | 0 | 0 | – |
| 2021-07-29 | Titusville, Mercer County | EF2 6.03 mi x 400 yd | 0 | 0 | – |
| 2019-08-07 | Windsor, Mercer County | EF0 0.33 mi x 25 yd | 0 | 0 | – |
| 2011-08-28 | Hightstown, Mercer County | EF0 0.6 mi x 30 yd | 0 | 0 | $33K |
| 2003-09-23 | Trenton, Mercer County | F1 5 mi x 100 yd | 0 | 0 | $1.6M |
| 1996-06-22 | Trenton, Mercer County | F0 2 mi x 220 yd | 0 | 0 | – |
| 1992-07-31 | Mercer County | F1 2.5 mi x 30 yd | 0 | 0 | $250K step |
| 1989-11-16 | Mercer County | F1 4 mi x 800 yd | 0 | 0 | $250K step |
| 1988-08-17 | Mercer County | F2 4.5 mi x 200 yd | 0 | 0 | $2.5M step |
| 1967-10-18 | Mercer County | F1 0.5 mi x 100 yd | 0 | 0 | $25K step |
| 1962-05-24 | Mercer County | F2 14.7 mi x 300 yd | 0 | 1 | $250K step |
| 1960-06-24 | Mercer County | 0 | 0 | $25K step | |
| 1958-06-13 | Mercer County | F2 | 0 | 0 | $250K step |
A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.
Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.
When was the last damaging storm in Mercer County?
The most recent record with damage, injuries or deaths is the September 1, 2021 flash flood (2 deaths and $55.5 million in damage in 2025 dollars).
Widespread flash flooding occurred in Mercer County with numerous road closures and nearly 100 water rescues. There were two flood related fatalities in the county, both in Hopewell Township. Many waterways overflowed their banks including the Assunpink Creek, Stony Brook and the Delaware River (with a highly unusual quick response to the runoff).
National Weather Service event narrative, NOAA Storm Events Database (search the full record, event 985743)
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-22 | Thunderstorm WindEast Trenton, Mercer County | 50 kt wind | 0 | 0 | – |
| 2026-06-22 | Flash FloodHamilton Square, Mercer County | 0 | 0 | – | |
| 2026-06-14 | Thunderstorm WindPrinceton, Mercer County | 50 kt wind | 0 | 0 | – |
| 2026-06-14 | Thunderstorm WindWhite Horse, Mercer County | 50 kt wind | 0 | 0 | – |
| 2026-06-06 | Thunderstorm WindEwing Township, Mercer County | 50 kt wind | 0 | 0 | – |
| 2026-05-20 | Thunderstorm WindHopewell, Mercer County | 55 kt wind | 0 | 0 | – |
| 2026-05-20 | Thunderstorm WindPennington, Mercer County | 50 kt wind | 0 | 0 | – |
| 2026-05-09 | Dense FogMercer County · forecast zone Mercer | 0 | 0 | – | |
| 2026-04-05 | Dense FogMercer County · forecast zone Mercer | 0 | 0 | – | |
| 2026-03-16 | Thunderstorm WindTrenton Airport, Mercer County | 50 kt wind | 0 | 0 | – |
| 2026-03-16 | Thunderstorm WindPenns Neck, Mercer County | 50 kt wind | 0 | 0 | – |
| 2026-03-16 | Thunderstorm WindRosedale, Mercer County | 50 kt wind | 0 | 0 | – |
Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.
The deadliest and costliest records
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2012-10-29 | High WindMercer County · forecast zone Mercer Post Tropical Storm Sandy was the costliest natural disaster by far in the state of New Jersey. Record breaking high tides and wave action combined with sustained winds as high as 60 to 70 mph with wind gusts as high as around 90 mph to batter the state. Statewide, Sandy caused an estimated 29.4 billion dollars in ... | 59 kt wind | 3 | 0 | $129M |
| 1999-07-04 | HeatMercer County · forecast zone Mercer A very strong and oppressive high pressure system that extended from the surface to aloft gave New Jersey a brutal heat wave that included the entire Independence Day weekend. There were seventeen heat related deaths and around 100 reported heat related injuries. High temperatures reached the 90s for the first time on ... | 3 | 0 | – | |
| 2021-09-01 | Flash FloodTitusville, Mercer County Widespread flash flooding occurred in Mercer County with numerous road closures and nearly 100 water rescues. There were two flood related fatalities in the county, both in Hopewell Township. Many waterways overflowed their banks including the Assunpink Creek, Stony Brook and the Delaware River (with a highly unusual ... | 2 | 0 | $56M | |
| 2011-08-28 | FloodHopewell, Mercer County In Princeton, a 39-year-old emergency responder died from injuries sustained while investigating a submerged vehicle in flood waters. No one was in the vehicle. In Lawrence Township, a 50-year-old man became trapped in a sewer pipe at Shemin Nurseries and drowned. Flooding along the Delaware River and Assunpink Creek ... | 2 | 0 | $98M | |
| 2012-05-29 | HeatMercer County · forecast zone Mercer The first back-to-back 90 degree days in and around the Philadelphia area during 2012 occurred in late May. It resulted in one heat related death in Mercer County and precipitated the early dismissal of school children in Camden on Tuesday the 29th. In Mercer County, a 47-year-old male became ill from the heat while ... | 1 | 0 | – | |
| 2011-07-21 | Excessive HeatMercer County · forecast zone Mercer One of the most oppressive heat waves since mid July 1995 enveloped New Jersey from July 21st through the 24th. The heat was responsible for two deaths and hundreds of heat related injuries. Many locations had high temperatures that reached into the 100s. The most oppressive day was July 22nd when the combination of ... | 1 | 0 | – | |
| 2002-09-11 | High WindMercer County · forecast zone Mercer The pressure difference between a strong high pressure system in the central part of the country and Tropical Storm Gustav located well east of the Delmarva Peninsula produced strong gusty northwest winds throughout the day on the 11th. Winds frequently gusted between 35 and 45 mph throughout the day and caused ... | 1 | 0 | – | |
| 1996-01-07 | BlizzardMercer County · forecast zone Mercer | 1 | 0 | $2.1M |
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2011-08-28 | FloodHopewell, Mercer County | 2 | 0 | $98M | |
| 1999-09-16 | Flash FloodCountywide, Mercer County | 0 | 5 | $57M | |
| 2021-09-01 | Flash FloodTitusville, Mercer County | 2 | 0 | $56M | |
| 1996-06-12 | Flash FloodWestern, Mercer County | 0 | 0 | $15M | |
| 2006-06-28 | FloodCountywide, Mercer County | 0 | 0 | $12M | |
| 2005-04-02 | FloodMercer County · forecast zone Mercer | 0 | 0 | $7.6M | |
| 2007-04-15 | FloodPrinceton, Mercer County | 0 | 0 | $7.1M | |
| 2004-09-19 | FloodMercer County · forecast zone Mercer | 0 | 0 | $3.7M |
Before 1993 NOAA filed damage by category, not amount, so the list above starts in 1993. The highest category filed here before then (entered as $2.5M, in the dollars of the day) holds: August 17, 1988 (tornado, Mercer County).
Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.
Is it getting more frequent?
Records per decade for Mercer County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).
| Hazard | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020-26 |
|---|---|---|---|---|---|---|---|---|
| Severe thunderstorm wind | 1 | 1 | 8 | 16 | 35 | 48 | 85 | 81 |
| Winter storms | – | – | – | – | 24 | 82 | 84 | 35 |
| Floods | – | – | – | – | 26 | 39 | 46 | 26 |
| High wind and dust storms | – | – | – | – | 18 | 68 | 39 | 3 |
| Heat | – | – | – | – | 27 | 34 | 23 | 8 |
| Hail | 0 | 0 | 2 | 7 | 10 | 12 | 15 | 17 |
Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).
What time of year?
52% of its severe thunderstorm wind events since 1955 fell in June and July. The two busiest months are in violet.
The values, month by month
Jan 143 · Feb 138 · Mar 94 · Apr 60 · May 69 · Jun 127 · Jul 178 · Aug 101 · Sep 52 · Oct 50 · Nov 48 · Dec 107 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began.
Federal disaster declarations for Mercer County
FEMA's register lists 28 declarations that include Mercer County: 17 major disasters, 11 emergencies and 0 fire management assistance declarations. Most were for hurricane (9) and severe storm (7).
| Declared | Number | Type | Title |
|---|---|---|---|
| 2021-09-05 | DR-4614 | Hurricane | Remnants of Hurricane Ida |
| 2021-09-02 | EM-3573 | Hurricane | Remnants of Hurricane Ida |
| 2020-03-25 | DR-4488 | Biological | Covid-19 Pandemic |
| 2020-03-13 | EM-3451 | Biological | Covid-19 |
| 2016-03-14 | DR-4264 | Severe Storm | Severe Winter Storm and Snowstorm |
| 2012-10-30 | DR-4086 | Hurricane | Hurricane Sandy |
| 2012-10-28 | EM-3354 | Hurricane | Hurricane Sandy |
| 2011-10-14 | DR-4039 | Severe Storm | Remnants of Tropical Storm Lee |
| 2011-08-31 | DR-4021 | Hurricane | Hurricane Irene |
| 2011-08-27 | EM-3332 | Hurricane | Hurricane Irene |
| 2011-02-04 | DR-1954 | Snowstorm | Severe Winter Storm and Snowstorm |
| 2010-04-02 | DR-1897 | Severe Storm | Severe Storms and Flooding |
| 2007-04-26 | DR-1694 | Severe Storm | Severe Storms and Inland and Coastal Flooding |
| 2006-07-07 | DR-1653 | Severe Storm | Severe Storms and Flooding |
| 2005-09-19 | EM-3257 | Hurricane | Hurricane Katrina Evacuation |
| 2005-04-19 | DR-1588 | Severe Storm | Severe Storms and Flooding |
| 2004-10-01 | DR-1563 | Severe Storm | Severe Storms and Flooding |
| 2003-03-20 | EM-3181 | Snowstorm | Snow |
| 2001-09-19 | EM-3169 | Fire | Fires and Explosions |
| 2000-11-01 | EM-3156 | Other | West Nile Virus |
| 1999-09-18 | DR-1295 | Hurricane | Hurricane Floyd Major Disaster Declarations |
| 1999-09-17 | EM-3148 | Hurricane | Hurricane Floyd Emergency Declarations |
| 1996-01-13 | DR-1088 | Snowstorm | Blizzard of 96 (Severe Snow Storm) |
| 1993-03-17 | EM-3106 | Snowstorm | Severe Blizzard |
| 1980-10-19 | EM-3083 | Drought | Water Shortage |
| 1975-07-23 | DR-477 | Flood | Heavy Rains, High Winds, Hail & Tornadoes |
| 1971-09-04 | DR-310 | Flood | Heavy Rains & Flooding |
| 1965-08-18 | DR-205 | Drought | Water Shortage |
Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.
How many floods has Mercer County had?
NOAA's Storm Events Database holds 137 flood or flash flood records for Mercer County from 1996 to 2026, on 114 days, with 4 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Mercer County ranks 164th of 2,942 U.S. counties.
| Storm | Began | Records | Deaths in the county |
|---|---|---|---|
| Hurricane Ida | 2021-09-01 | 1 | 2 |
| Hurricane Irene | 2011-08-27 | 3 | 2 |
| Hurricane Sandy | 2012-10-30 | 1 | 0 |
| Hurricane Floyd | 1999-09-16 | 1 | 0 |
The National Flood Insurance Program has paid $48.4 million on 2,432 claims filed in Mercer County; the most in one year was 408 in 2011. Claims count insured losses only: uninsured flood damage is not in this file.
The values, year by year
1978: 98 · 1979: 134 · 1980: 18 · 1981: 28 · 1982: 10 · 1983: 28 · 1984: 34 · 1985: 2 · 1986: 2 · 1987: 118 · 1989: 27 · 1990: 2 · 1991: 5 · 1992: 13 · 1993: 7 · 1994: 69 · 1996: 237 · 1997: 3 · 1998: 2 · 1999: 130 · 2000: 3 · 2001: 18 · 2002: 2 · 2003: 14 · 2004: 153 · 2005: 226 · 2006: 243 · 2007: 82 · 2008: 2 · 2009: 20 · 2010: 24 · 2011: 408 · 2012: 16 · 2013: 12 · 2014: 12 · 2015: 5 · 2016: 12 · 2017: 1 · 2018: 19 · 2019: 5 · 2020: 4 · 2021: 161 · 2022: 3 · 2023: 5 · 2024: 12 · 2025: 1 · 2026: 2; the other years: 0.
Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.
FEMA's modeled risk for Mercer County
FEMA's National Risk Index rates Mercer County Relatively High overall, with an expected annual loss of $176 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.
| Hazard | Risk rating | Expected annual loss | Modeled frequency |
|---|---|---|---|
| Strong Wind | Very High | $13M | 7 a year (modeled) |
| Winter Weather | Very High | $1.1M | 11 a year (modeled) |
| Ice Storm | Very High | $1.9M | 1.1 a year (modeled) |
| Riverine Flooding | Relatively High | $114M | 3.6 a year (modeled) |
| Hurricane | Relatively High | $18M | once in about 9 years (modeled) |
| Lightning | Relatively High | $1.5M | 34 a year (modeled) |
| Heat Wave | Relatively Moderate | $6.8M | 11 modeled event-days a year |
| Earthquake | Relatively Moderate | $11M | once in about 532 years (modeled) |
Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.
Counties that share a border with Mercer County
Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.
Next
- Tornadoes in New JerseyEvery New Jersey tornado since 1950 and the counties with the most per square mile
- Severe thunderstorm wind in New JerseyThe state's severe thunderstorm wind events, by county, year and month
- The New Jersey recordEvery hazard in the state, its deadliest events and its federal declarations
- FEMA's risk rating for each hazard in Mercer CountyThe hazard risk calculator: 18 hazards beside the county's record
- Download Mercer County's FEMA declarations (CSV)28 rows: every declaration that named the county, for your own analysis