Mercer County, Missouri
Natural disaster risk, federal disaster history and flood insurance facts.
Mercer County, Missouri has a very low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is lower than 88% of US counties. It ranks 111th of 115 counties in Missouri. The costliest hazards here are inland flooding, tornadoes and drought. FEMA estimates about $4.0 million a year in expected losses, or roughly $1,118 per resident. Since 1973 it has been included in 18 federal disaster or emergency declarations for natural events (13 major disasters). The most recent was in August 2026 (severe storms, straight-line winds, tornadoes and flooding). No homes here carry federal flood insurance.
FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.
Top risks in Mercer County
- Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
- Price a flood policy now. Most new federal policies take 30 days to start.
- Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
- Turn on emergency alerts on your phone and keep a weather radio.
- Check local water restrictions.
- Choose drought-tolerant plants.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 17.9 | $2M | ||
| Tornado | 44.0 | $755K | ||
| Drought | 77.4 | $587K | ||
| Cold wave | 34.8 | $389K | ||
| Heat wave | 46.3 | $230K | ||
| Hail | 42.5 | $145K | ||
| Strong wind | 20.5 | $138K | ||
| Wildfire | 48.3 | $32K | ||
| Lightning | 9.4 | $23K | ||
| Earthquake | 17.2 | $16K | ||
| Winter weather | 17.1 | $11K | ||
| Landslide | 79.0 | $11K | ||
| Ice storm | 9.1 | $3K | ||
| Hurricane | 11.4 | $2K |
Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is relatively high and community resilience is very low in FEMA's measures.
Federal disaster history
Recent disasters nationwide ›Declarations by decade
Federal declarations for natural events that included Mercer County. 2020s bar runs to November 2026.
By type
Most recent
Show all 18
Missouri also had 5 statewide declarations that did not name single counties.
Storm history since 1955
Tornado risk by county ›The National Weather Service has logged 187 storm reports in Mercer County since 1955, with 0 deaths and 1 injury and about $525,030 in reported damage. The strongest on record here was an F4 tornado on April 21, 1973.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Apr 21, 1973 | F4 | – | 1 / 0 |
| Sep 26, 1959 | F2 | – | 0 / 0 |
| Sep 26, 1959 | F2 | – | 0 / 0 |
| Apr 16, 1960 | F2 | – | 0 / 0 |
| Apr 16, 1960 | F2 | – | 0 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Apr 21, 1973 | Tornado | – | $250K |
| Jun 15, 1958 | Tornado | – | $25K |
| May 20, 1959 | Tornado | – | $25K |
| Sep 26, 1959 | Tornado | – | $25K |
| Sep 26, 1959 | Tornado | – | $25K |
| Jun 4, 1960 | Tornado | – | $25K |
Source: NOAA Storm Events Database, county-based reports through Sep 17, 2025. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.
Flood insurance in Mercer County
Check your address flood zone ›National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.
Homes in Mercer County
Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 1,902 housing units.
Compare in Missouri
All 115 ›| Largest counties | Overall risk | Top hazard |
|---|---|---|
| St. Louis County | Heat wave | |
| Jackson County | Inland flooding | |
| St. Charles County | Inland flooding | |
| St. Louis City | Heat wave | |
| Greene County | Inland flooding | |
| Clay County | Inland flooding | |
| Jefferson County | Inland flooding | |
| Boone County | Inland flooding |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Grundy County | 20 | |
| Harrison County | 17 | |
| Decatur County, IA | 12 | |
| Wayne County, IA | 13 | |
| Sullivan County | 23 | |
| Putnam County | 17 |
Common questions about Mercer County
What is the biggest natural hazard in Mercer County?
Inland flooding has the highest expected yearly losses in Mercer County, about $1.6 million a year in FEMA's estimate. Tornado is second at $754,659.
How many federal disasters has Mercer County had?
Mercer County has been included in 18 federal disaster or emergency declarations for natural events since 1973, including 13 major disasters. The most recent was Severe Storms, Straight-Line Winds, Tornadoes, and Flooding in August 2026.
Is Mercer County a high-risk place to live?
Its overall rating is Very Low, 111th highest of 115 in Missouri. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.
Do I need flood insurance in Mercer County?
Standard home insurance does not cover flooding. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.
How many tornadoes has Mercer County had?
NOAA records list 17 tornadoes in Mercer County since 1950. The strongest was an F4 tornado on April 21, 1973. The weather service has also logged 89 hail reports and 13 floods here.
Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.