Union County, Tennessee: Natural Disaster Risk and History
Union County, Tennessee has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 12.9 out of 100, higher than about 12% of US counties, with landslides, earthquakes and wildfires scoring highest of its 18 hazards and $5.1 million a year in expected losses.
OpenFEMA lists 14 federal disaster declarations that included Union County since 1973, not counting 2 for COVID-19; the latest is DR-4898-TN (Severe Winter Storm, declared 6 February 2026). NOAA's Storm Prediction Center recorded 3 tornadoes touching Union County from 1950 to 2025.
Live weather alerts for Tennessee All official warnings Latest FEMA declarations
Population 19,802 Buildings worth $3.1 billion Area 250 sq mi Risk rank in Tennessee 88 of 95 FIPS 47173
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Landslide | Relatively Moderate | 88.3 | $42,710 | about once every 1.1 years | — |
| Earthquake | Relatively Low | 60.0 | $418,996 | about once every 243 years | — |
| Wildfire | Very Low | 50.4 | $45,011 | about once every 331 years | — |
| Strong wind | Relatively Low | 40.7 | $389,467 | about 5.2 a year | 198 |
| Winter weather | Relatively Low | 39.8 | $41,785 | about 5.3 a year | 101 |
| Lightning | Relatively Low | 37.3 | $133,799 | about 54 a year | 38,026 strikes |
| Tornado | Relatively Low | 35.3 | $627,663 | about once every 13 years | 1 |
| Cold wave | Relatively Low | 32.5 | $435,294 | about once every 1.4 years | 14 |
| Ice storm | Relatively Low | 28.3 | $26,463 | about once every 3.2 years | 22 |
| Hail | Very Low | 26.7 | $92,836 | about 3 a year | 114 |
| Inland flooding | Very Low | 26.0 | $2.8 million | about once every 1.6 years | 17 |
| Hurricane | Very Low | 23.0 | $7,026 | about once every 95 years | 2 |
| Heat wave | Very Low | 11.6 | $21,450 | about once every 2.1 years | 9 |
| Drought | No Rating | 0.0 | — | about 16 a year | 406 |
| Avalanche | Not Applicable | — | — | — | — |
| Coastal flooding | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic activity | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 14
Most common: Severe Storm 7, Flood 3, Winter Storm 2, Hurricane 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1970s | 1 | Flood |
| 1980s | 1 | Flood |
| 1990s | 4 | Severe Storm ×3, Snowstorm |
| 2000s | 3 | Severe Storm ×2, Hurricane |
| 2010s | 2 | Flood, Severe Storm |
| 2020s | 3 | Winter Storm ×2, Severe Storm |
The last 10
Widest declarations that included Union County
- Severe Winter Storm (2026, DR-4898-TN): 95 Tennessee counties designated.
- Severe Winter Storm (2026, EM-3635-TN): 95 Tennessee counties designated.
- Severe Storms, Straight-Line Winds, Tornadoes, and Flooding (2025, EM-3625-TN): 95 Tennessee counties designated.
Named storms in its declarations: Hurricane Katrina (2005).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. Tennessee also had 1 statewide declaration with no county list.
Tornado record since 1950 3
| Tornadoes touching the county | 3 |
|---|---|
| Strongest-rated | (E)F1 ×1 |
| Peak month | April (1) |
| Deadliest | — |
| Longest path | 4 Apr 1974, F0, 8.7 mi path |
| Most recent | 8 May 2009, EF0, 0.8 mi path |
| Deaths / injuries on those paths | 0 / 0 |
| Rating | (E)F0 | (E)F1 | (E)F2 | (E)F3 | (E)F4 | (E)F5 | Unrated |
|---|---|---|---|---|---|---|---|
| Count | 2 | 1 | 0 | 0 | 0 | 0 | 0 |
| Decade | 1950s | 1960s | 1970s | 1980s | 1990s | 2000s | 2010s | 2020s |
|---|---|---|---|---|---|---|---|---|
| Count | 0 | 0 | 2 | 0 | 0 | 1 | 0 | 0 |
Deaths and injuries are for each tornado's whole path, which can run beyond this county. F-scale ratings before February 2007, Enhanced Fujita (EF) after.
How Union County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Union County (this page) | — | Very Low | 12.9 | Landslide |
| Claiborne County | 27 km | Relatively Low | 42.8 | Landslide |
| Grainger County | 29 km | Very Low | 18.6 | Landslide |
| Campbell County | 31 km | Relatively Low | 58.0 | Landslide |
| Knox County | 34 km | Relatively Moderate | 92.1 | Lightning |
| Anderson County | 37 km | Relatively Low | 73.2 | Landslide |
Nearest by distance between county centres. Every county in Tennessee, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively Moderate 46.9 |
|---|---|
| Community resilience | Very Low 13.1 |
| Community risk factor | 1.13 |
| Expected annual loss, all hazards | $5.1 million |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for Union County's main hazards
- Right now: National Weather Service alerts for Tennessee · all official warnings on Global Incident Tracker.
- Landslide: Landslides recorded
- Earthquake: Earthquakes today · Earthquake safety guide
- Wildfire: US wildfires now · Wildfire smoke: what protects you
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets 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).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. 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).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about Union County
What natural disasters is Union County, Tennessee most at risk from?
Union County, Tennessee has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 12.9 out of 100, higher than about 12% of US counties, with landslides, earthquakes and wildfires scoring highest of its 18 hazards and $5.1 million a year in expected losses.
How many federal disaster declarations has Union County had?
OpenFEMA lists 14 federal disaster declarations that included Union County since 1973, not counting 2 for COVID-19; the latest is DR-4898-TN (Severe Winter Storm, declared 6 February 2026). Another 1 Tennessee declarations were made statewide without a county list.
How many tornadoes have hit Union County?
NOAA's Storm Prediction Center recorded 3 tornadoes touching Union County from 1950 to 2025.
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.