Mercer County, PA
FEMA National Risk Index scores, disaster declarations & hazard data
Mercer County has experienced 13 federally declared disasters since 1972, most recently Covid-19 in 2020. Its overall natural hazard risk is rated Relatively Low — lower risk than most US counties.
Mercer County's highest-rated hazards are inland flooding, lightning, and winter weather, with its top risk rated "Relatively Moderate" by FEMA's National Risk Index. Recorded storm events have decreased 46% over the past five years compared to the prior five-year period.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Mercer County has been designated in 13 declarations since 1972, covering 6 disaster types including hurricane (3), flood (3), biological (2).
| Year | Type | Event name |
|---|---|---|
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2013 | Hurricane | Hurricane Sandy |
| 2005 | Hurricane | Hurricane Katrina |
| 2004 | Hurricane | Tropical Depression Ivan |
| 2004 | Severe Storm | Severe Storms And Flooding Associated With Tropical Depression Frances |
| 2003 | Severe Storm | Severe Storms, Tornadoes, And Flooding |
| 1996 | Flood | Severe Storms And Flooding |
| 1993 | Snowstorm | Severe Snowfall & Winter Storm |
| 1985 | Tornado | Severe Storms, High Winds & Tornadoes |
Showing the 10 most recent of 13 total declarations since 1972.
Source: FEMA OpenFEMA Disaster Declarations Summaries. A single disaster can produce more than one record per county. Data current through September 2026.
Risk by hazard type
| Hazard | Risk rating | Risk score | Recorded events | Deaths | Prop. damage |
|---|---|---|---|---|---|
| Wildfire | Very Low | 36.4 | 0 | 0 | — |
| Inland Flooding | Relatively Moderate | 87.9 | 37 | 0 | $128K |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Very Low | 51.5 | 1 | — | — |
| Heat Wave | Very Low | 28.4 | 0 | 0 | — |
| Tornado | Relatively Low | 55.3 | 4 | 0 | $8K |
| Hurricane | Relatively Low | 64.8 | 0 | 0 | — |
| Hail | Relatively Moderate | 75.9 | 36 | 0 | $38K |
| Strong Wind | Relatively Moderate | 74 | 0 | 0 | — |
| Winter Weather | Relatively Moderate | 77.9 | 0 | 0 | — |
| Ice Storm | Relatively Low | 42.2 | — | — | — |
| Cold Wave | Very Low | 23.2 | — | — | — |
| Lightning | Relatively High | 87.3 | 0 | 0 | — |
| Drought | No Rating | 0 | 0 | 0 | — |
| Landslide | Very Low | 43.1 | 0 | 0 | — |
| Avalanche | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic Activity | Not Applicable | — | — | — | — |
Scores are 0–100 percentiles relative to all US counties — higher means more exposed, not that a disaster is likely this year. Event counts: NOAA Storm Events 2016–2026; earthquake counts from USGS ComCat (M3.0+, 1996–2026). See the methodology page for details.
Community vulnerability
Mercer County ranks in the 53rd percentile (Moderate) for community vulnerability — a measure of how hard disaster impacts tend to hit residents. Higher vulnerability means more displacement, worse health outcomes, and slower recovery after a disaster.
| SVI theme | Percentile | Vulnerability level |
|---|---|---|
| Overall | 53rd | Moderate |
| Socioeconomic status | 38th | Low |
| Household characteristics | 58th | Moderate |
| Racial & ethnic minority status | 32nd | Low |
| Housing type & transportation | 76th | High |
Source: CDC/ATSDR Social Vulnerability Index 2022. Percentiles compare counties nationally — higher means more vulnerable relative to other counties. See CDC SVI for full methodology.
Future risk outlook
| Wildfire metric | National percentile | Level |
|---|---|---|
| Burn probability | 23rd | Relatively Low |
| Risk to homes | 22nd | Relatively Low |
| Buildings in direct exposure zone | 60.4% | — |
NOAA tracked 77 weather events in this county over 2016–2025: 50 in 2016–20 vs 27 in 2021–25 (-46% — frequency decreasing).
Wildfire: USDA Forest Service Wildfire Risk to Communities (RDS-2020-0016-2) — modeled values, not annual forecasts. See wildfirerisk.org. Inland flood and heat projections pending data availability; coastal sea-level projections are available for select coastal counties below — see the data page.
Nearby counties
Frequently asked questions
What natural hazards pose the greatest risk in Mercer County?
According to the FEMA National Risk Index, the highest-risk hazards in Mercer County, Pennsylvania are inland flooding, lightning, and winter weather. The county's overall natural hazard risk is rated Relatively Low — lower risk than most US counties.
Has Mercer County received federal disaster declarations?
Yes. Mercer County has received 13 federal disaster declarations since 1972, including declarations in 2020. The most common disaster type on record is hurricane (3 declarations).
Has Mercer County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Mercer County since the start of 2024. Its most recent declaration on record is Covid-19 in 2020.
How does Mercer County's natural hazard risk compare to nearby counties?
Among neighboring counties, Trumbull County, OH has the highest overall natural hazard risk (Relatively Moderate) and Venango County, PA has the lowest (Relatively Low). Mercer County is rated Relatively Low overall.
How is Mercer County's composite disaster risk index calculated?
Mercer County's composite disaster risk index — officially FEMA's National Risk Index (NRI) — scores every US county on a 0–100 percentile scale across 18 natural hazard types, factoring in expected annual loss, social vulnerability, and community resilience. Mercer County's composite score of 78 means its overall natural hazard risk is higher than 78% of US counties.