Mercer County, Ohio
Recorded hazard history: storm events since 1950, federal disaster declarations since 1953, flood insurance claims since 1978, and FEMA's risk index.
NCEI notes that Storm Data is compiled from a variety of sources including the National Weather Service, other federal, state and local agencies, the media and the public; that property and crop damage figures are estimates; and that some events are recorded by NWS forecast zone rather than by county. FEMA notes that NFIP claim records are redacted and aggregated to protect the privacy of policyholders. NCEI storm records through 30 Jun 2026; OpenFEMA declarations refreshed 1 Oct 2026; NFIP claims as of 8 Sep 2026.
Mercer County, Ohio, has 544 weather events in the NCEI Storm Events record since 1950, most of them damaging wind.
That is 117.6 events per 100 square miles, in line with the Ohio figure of 126.7, and 128.6 per 10,000 residents against 44.0 statewide.
16 events fall in the 12 months to 30 Jun 2026. NCEI attributes 3 deaths and 58 injuries to events in the county, with property damage estimated at $53M and crop damage at $650K.
FEMA has designated the county in 14 federal disaster declarations since 1953; the most recent is Tornadoes (major disaster, 2 May 2024).
National Flood Insurance Program policyholders in the county filed 96 claims since 1978, of which 82 were paid, totalling $1.3M (about $16K per paid claim). FEMA counts 56 residential flood policies in force.
FEMA's National Risk Index rates the county's overall risk as "Very Low" and its expected annual loss as "Relatively Low" ($18M a year across 18 hazards).
4 tropical storm or hurricane tracks in the HURDAT2 record passed within 100 miles of the county's centre at tropical-storm strength or more, 0 of them within 50 miles at hurricane strength.
Compared with Ohio and the United States
| Measure | Mercer County | Ohio | US |
|---|---|---|---|
| Recorded events since 1950 | 544 | 51,777 | 1,977,440 |
| Events per 100 square miles | 117.6 | 126.7 | 56.0 |
| Events per 10,000 residents | 128.6 | 44.0 | 59.6 |
| Events in the last 12 months | 16 | 1,442 | 62,008 |
| Deaths recorded by NCEI | 3 | 460 | 26,435 |
| Property damage (NCEI estimates) | $53M | $8.4B | $575B |
| NFIP claims per 1,000 residents | 2.3 | 2.4 | 8.1 |
| Average paid NFIP claim | $16K | $17K | $43K |
| Claims per 100 policies in force, last 10 years | 32.1 | 16.2 | 16.1 |
County-recorded events plus zone-recorded events whose forecast zone is named for the county. State and US rows include events recorded only by forecast zone. Rates use 2021 Census population and land area.
Events by decade
Trend: 322 events in the 20 years to 2025 against 173 in the 20 years before. Reporting practice changed in 1996 and again with automated reports in the 2000s, so decade totals measure the record as much as the weather.
Events by type
Hazard pages exist for hail, tornado, flood, wind and winter where the county has at least 10 recorded events. "Other" covers heavy rain, debris flow, dust, funnel clouds and similar reports.
Largest recorded events
| Date | Event type | Group | Magnitude | Property damage | Crop damage | Deaths | Injuries | Geography |
|---|---|---|---|---|---|---|---|---|
| 11 Apr 1965 | Tornado | Tornado | F4 | $2.5M | — | 2 | 24 | County |
| 27 May 2019 | Tornado | Tornado | EF3 | $15M | — | 1 | 8 | County |
| 5 Nov 2017 | Tornado | Tornado | EF2 | $5.0M | — | — | 8 | County |
| 9 Mar 2002 | High Wind | Wind | 63 mph | $35K | — | — | 7 | Forecast zone |
| 1 Jun 1980 | Tornado | Tornado | F1 | $2.5M | — | — | 4 | County |
| 5 Nov 2017 | Tornado | Tornado | EF2 | $11M | $30K | — | — | County |
| 25 Jun 2002 | Thunderstorm Wind | Wind | — | $50K | — | — | 1 | County |
| 29 Jun 2012 | Thunderstorm Wind | Wind | 81 mph | $30K | — | — | 1 | County |
| 26 Nov 1965 | Tornado | Tornado | F1 | $25K | — | — | 1 | County |
| 1 Dec 2006 | High Wind | Wind | 44 mph | $15K | — | — | 1 | Forecast zone |
| 29 Jun 2012 | Thunderstorm Wind | Wind | 81 mph | $10K | — | — | 1 | County |
| 2 Jul 1994 | Thunderstorm Wind | Wind | 0 mph | $5K | — | — | 1 | County |
| 13 Jun 2000 | Lightning | Lightning | — | — | — | — | 1 | County |
| 14 Sep 2008 | High Wind | Wind | 60 mph | $4.9M | — | — | — | Forecast zone |
| 8 Jul 2003 | Flash Flood | Flood | — | $2.0M | — | — | — | County |
| 18 Jun 2021 | Tornado | Tornado | EF2 | $1.0M | $50K | — | — | County |
| 7 Jul 2003 | Flash Flood | Flood | — | $1.0M | — | — | — | County |
| 8 Jul 2003 | Flash Flood | Flood | — | $1.0M | — | — | — | County |
| 6 Apr 2007 | Frost/Freeze | Cold | — | — | $540K | — | — | Forecast zone |
| 6 Jan 1996 | Winter Storm | Winter | — | $500K | — | — | — | Forecast zone |
Ranked by deaths, then injuries, then NCEI's damage estimate. Deaths and injuries are NCEI counts (direct plus indirect); no personal details are recorded here.
Federal disaster declarations
| Declared | Number | Type | Incident | Title | Programs |
|---|---|---|---|---|---|
| 2 May 2024 | DR-4777 | Major disaster | Tornado | Tornadoes | Individual assistance |
| 31 Mar 2020 | DR-4507 | Major disaster | Biological | Covid-19 Pandemic | Individual assistance, Public assistance |
| 13 Mar 2020 | EM-3457 | Emergency | Biological | Covid-19 | Public assistance |
| 18 Jun 2019 | DR-4447 | Major disaster | Tornado | Severe Storms, Straight-Line Winds, Tornadoes, Flooding, Landslides, And Mudslide | Individual assistance, Public assistance |
| 30 Jun 2012 | EM-3346 | Emergency | Severe Storm | Severe Storms | Public assistance |
| 13 Sep 2005 | EM-3250 | Emergency | Hurricane | Hurricane Katrina Evacuation | Public assistance |
| 15 Feb 2005 | DR-1580 | Major disaster | Severe Storm | Severe Winter Storms, Flooding, And Mudslides | Public assistance |
| 19 Sep 2004 | DR-1556 | Major disaster | Severe Storm | Severe Storms And Flooding | — |
| 15 Jul 2003 | DR-1478 | Major disaster | Severe Storm | Severe Storms And Flooding | Individual assistance |
| 25 Aug 1995 | DR-1065 | Major disaster | Severe Storm | Severe Storms And Flooding | Individual assistance |
| 4 Aug 1992 | DR-951 | Major disaster | Severe Storm | Severe Storms, Tornadoes & Flooding | Individual assistance, Public assistance |
| 10 Jun 1989 | DR-831 | Major disaster | Flood | Severe Storms & Flooding | Individual assistance |
| 26 Jan 1978 | EM-3055 | Emergency | Snowstorm | Blizzards & Snowstorms | Public assistance |
| 14 Apr 1965 | DR-191 | Major disaster | Tornado | Tornadoes & Severe Storms | Individual assistance, Public assistance |
Declarations in which FEMA designated this county, from the OpenFEMA Disaster Declarations Summaries (v2). DR: major disaster; EM: emergency; FM: fire management assistance. Programs show whether individual or public assistance was made available.
Flood insurance claims
| Year of loss | Claims | Paid claims | Amount paid | Average paid |
|---|---|---|---|---|
| 2020 | 1 | 0 | $0 | — |
| 2019 | 16 | 15 | $327,329 | $21,822 |
| 2017 | 1 | 1 | $26,636 | $26,636 |
| 2015 | 6 | 5 | $146,124 | $29,225 |
| 2011 | 9 | 6 | $150,133 | $25,022 |
| 2008 | 7 | 7 | $142,830 | $20,404 |
| 2006 | 2 | 2 | $28,654 | $14,327 |
| 2005 | 11 | 10 | $125,968 | $12,597 |
| 2003 | 7 | 6 | $87,405 | $14,567 |
| 1998 | 1 | 1 | $1,009 | $1,009 |
| 1997 | 1 | 1 | $7,240 | $7,240 |
| 1995 | 13 | 12 | $201,689 | $16,807 |
| 1993 | 16 | 13 | $96,258 | $7,404 |
| 1992 | 3 | 2 | $5,273 | $2,637 |
| 1989 | 1 | 0 | $0 | — |
| 1980 | 1 | 1 | $1,406 | $1,406 |
OpenFEMA NFIP claims (v3, as of 8 Sep 2026), aggregated by year of loss; amounts are building, contents and increased-cost-of-compliance payments as recorded. Repetitive-loss counts from the NFIP Multiple Loss Properties file (2 Aug 2026); policies in force from the NFIP Residential Penetration Rates file (3 Aug 2026).
National Risk Index
| Hazard (NRI) | Risk rating | Expected annual loss |
|---|---|---|
| Inland flooding | $9,191,077 | |
| Tornado | $4,031,321 | |
| Earthquake | $1,843,825 | |
| Strong wind | $940,742 | |
| Hail | $769,253 | |
| Cold wave | $759,220 | |
| Lightning | $161,591 | |
| Ice storm | $118,589 | |
| Heat wave | $83,238 | |
| Hurricane | $48,811 | |
| Winter weather | $48,303 | |
| Wildfire | $3,589 | |
| Landslide | $225 |
FEMA National Risk Index, December 2025 release. Ratings are FEMA's relative comparison of counties; expected annual loss is FEMA's modelled estimate of average yearly building, population and agriculture loss. See how to read the NRI.
Hurricane and tropical storm passes
| Storm | Year | Closest approach | Max wind while within 100 mi |
|---|---|---|---|
| Unnamed Atlantic storm | 1923 | 94 mi | 40 mph |
| Unnamed Atlantic storm | 1915 | 12 mi | 40 mph |
| Unnamed Atlantic storm | 1902 | 41 mi | 40 mph |
| Unnamed Atlantic storm | 1892 | 94 mi | 52 mph |
HURDAT2 best-track positions at tropical-storm strength (34 kt) or more, measured from the county's Census centre point; through the 2025 season. Distance from a track is not the same as the extent of the storm's wind, rain or surge.
ZIP codes with flood claims
ZIP codes whose NFIP claims carry this county's code, with the number of claims. Five or more claims are needed for a ZIP page to be indexed.
Questions and answers
How often does it hail in Mercer County, OH?
NCEI records 74 hail events in Mercer County since 1950, in 29 different years; that is about 1.0 recorded events a year. 7 reports were golf-ball size (1.75 in) or larger.
Has Mercer County had a tornado?
Yes. NCEI records 29 tornadoes in Mercer County since 1950, 8 of them rated (E)F2 or stronger. Tornado deaths recorded: 3.
When was the last federal disaster declaration for Mercer County?
2 May 2024: Tornadoes, a major disaster declaration for tornado. The county appears in 14 declarations since 1953.
How many flood insurance claims have been filed in Mercer County, and how much was paid?
96 NFIP claims since 1978, 82 of them paid, for $1.3M in total. FEMA publishes these figures redacted and aggregated; individual properties are not identified.
Is Mercer County in the National Risk Index's high-risk band?
FEMA's National Risk Index (December 2025) rates the county "Very Low" for overall risk, "Relatively Low" for expected annual loss, "Very Low" for social vulnerability and "Very High" for community resilience. These ratings are FEMA's relative comparison across all US counties.
How does Mercer County compare with the rest of Ohio?
117.6 recorded events per 100 square miles against 126.7 statewide, and 2.3 NFIP claims per 1,000 residents against 2.4. The comparison table on this page shows each measure beside the state and national figures.
Provenance
Storm events: NOAA NCEI Storm Events Database, yearly details files through 30 Jun 2026 (public domain). Declarations: OpenFEMA DisasterDeclarationsSummaries v2, refreshed 1 Oct 2026. Flood claims: OpenFEMA NfipClaims v3 as of 8 Sep 2026; NfipMultipleLossProperties v1 (2 Aug 2026); NfipResidentialPenetrationRates v1 (3 Aug 2026). Risk index: FEMA National Risk Index, December 2025. Hurricane tracks: NHC HURDAT2 through 2025. Population and area: US Census Bureau, 2021 vintage. Built 1 Oct 2026; see the methodology and corrections pages. Hazard hubs: Hail · Tornado · Flood · Wind · Winter.