Natural disaster risk in Mercer County, Ohio
Ohio · population 42,522 · FIPS 39107
Overall: very low risk
Mercer County has a composite risk score of 31.6 out of 100 — higher than 31% of US counties. It ranks 73 of 88 in Ohio (1 = highest risk). Its highest-rated hazards are tornado, earthquake, hail.
Drought now: No: no drought or dryness
No. On the U.S. Drought Monitor map valid 13 October 2026, no part of Mercer County is in drought or abnormally dry (none of D0 to D4). That has been so for 26 weeks in a row.
Drought in Mercer County: the last 52 weeks · droughtmonitor.unl.edu
The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration. Map courtesy of NDMC.
Risk, loss, vulnerability and resilience
| Measure | Rating and score |
|---|---|
| Overall risk Expected annual loss, adjusted for social vulnerability and community resilience. |
Very low 31.6 |
| Expected annual loss About $18.0 million a year, on average, across all 18 hazards. |
Relatively low 56.8 |
| Social vulnerability Higher means people may find it harder to prepare and recover. |
Very low 10.6 |
| Community resilience Higher means a stronger ability to prepare, adapt and recover. |
Very high 96.2 |
Risk by hazard
FEMA's risk rating for each of 18 natural hazards in Mercer County, highest first. "Not applicable" means the hazard is not modelled here.
| Hazard | Risk rating and score |
|---|---|
| Tornado | Relatively moderate 67 |
| Earthquake | Relatively low 73 |
| Hail | Relatively low 64 |
| Strong wind | Relatively low 48 |
| Ice storm | Relatively low 45 |
| Inland (riverine) flooding | Relatively low 42 |
| Cold wave | Relatively low 30 |
| Winter weather | Relatively low 28 |
| Lightning | Relatively low 25 |
| Hurricane | Very low 38 |
| Landslide | Very low 20 |
| Heat wave | Very low 17 |
| Wildfire | Very low 6 |
| Avalanche | Not applicable |
| Coastal flooding | Not applicable |
| Drought | No rating |
| Tsunami | Not applicable |
| Volcanic activity | Not applicable |
FEMA disaster declarations for Mercer County
Federal declarations that designated Mercer County, since 1 Jan 2024 (the period this site keeps from OpenFEMA). Older declarations are in FEMA's own dataset.
Yes. Mercer County has been named in 1 FEMA declaration since 1 Jan 2024. The latest is DR-4777-OH (Tornadoes), declared 2 May 2024.
| Declaration | Kind | Incident | Declared | Individual assistance here |
|---|---|---|---|---|
| DR-4777-OH | Major disaster | Tornadoes | 2 May 2024 | Yes |
All FEMA declarations in Ohio, with estimated apply-by dates · Open FEMA deadlines
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s). Dataset: Disaster Declarations Summaries - v2.
How to read these ratings
- Ratings run in five steps: very low, relatively low, relatively moderate, relatively high and very high. They compare a county with every other US county; they are not a measure of danger on their own.
- Scores run from 0 to 100 and are national percentiles. The bar shows the score: a score of 80 means a higher value than 80% of US counties.
- Overall risk combines the expected annual loss with social vulnerability and community resilience.
- Expected annual loss is the average yearly loss to buildings, people and agriculture the model expects from all 18 hazards.
- Social vulnerability describes how hard it may be for people to prepare for and recover from a disaster. Higher is worse.
- Community resilience describes a community's ability to prepare, adapt and recover. Higher is better.
- "Not applicable" means FEMA does not model that hazard there (for example, hurricanes far inland).
About this data
Source: FEMA National Risk Index, version 1.20, released December 2025, published by the Federal Emergency Management Agency (US public domain). About the National Risk Index. The index is a model of relative risk built from historical hazard records, what is exposed and community factors. It is not a forecast, it does not describe any single property, and it is not insurance or financial advice. For decisions about a specific address, check FEMA's flood maps and your local emergency management office.
Questions
What is the natural disaster risk in Mercer County, Ohio?
FEMA's National Risk Index rates the overall risk in Mercer County as very low, with a score of 31.6 out of 100 (higher than 31% of US counties). That is a comparison with other US counties, not a forecast.
What are the biggest natural hazards in Mercer County?
The hazards rated highest for Mercer County are tornado (relatively moderate), earthquake (relatively low), hail (relatively low).
What is the flood risk in Mercer County?
FEMA rates inland (river and rain) flooding risk in Mercer County as relatively low. For a specific property, check the FEMA flood map and your local floodplain office.
Has Mercer County had a FEMA disaster declaration?
Yes. Mercer County has been named in 1 FEMA declaration since 1 Jan 2024. The latest is DR-4777-OH (Tornadoes), declared 2 May 2024.
Is Mercer County in a drought?
No. On the U.S. Drought Monitor map valid 13 October 2026, no part of Mercer County is in drought or abnormally dry (none of D0 to D4). That has been so for 26 weeks in a row.
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