Union County, Tennessee Natural Disaster Risk
FEMA National Risk Index assessment · TN
Very LowComposite Risk Score
National percentile: 13th
Union County faces very low composite natural disaster risk (NRI Risk Index score 12.9, 13th national percentile), driven primarily by landslide and earthquake exposure. Expected annual loss across all 18 hazard types is $5M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Union County at very low composite risk, with a National Risk Index score of 12.9 out of 100 — placing it in the 13th national percentile and among the lowest-risk counties in the country. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in landslide (downhill movement of rock, soil, and debris on unstable slopes) at Medium risk — $43K in expected annual loss and about 0.92 events per year; earthquake (ground shaking from sudden movement along geologic faults) at Low risk — $419K in expected annual loss and about 0.00 events per year; and wildfire (uncontrolled fires that spread across wildland and into communities) at Very Low risk — $45K in expected annual loss and about 0.00 events per year. Across all hazards, FEMA estimates $5M in expected annual loss for a population of 20K.
Beyond physical exposure, Union County has a medium social vulnerability rating (how susceptible the population is to harm) and a very low community resilience rating (its capacity to prepare for and recover from disasters). Both measures sit toward the lower end, indicating relatively modest population sensitivity.
History supports the rating: Union County has received 16 federal disaster declarations since 1973, including 7 for severe storm events and 3 for flood events. The most recent was Severe Winter Storm (winter storm), declared in February 2026.
Among 95 Tennessee counties, Union County ranks #88 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Landslide | Medium | 0.92 / yr | $43K |
| Earthquake | Low | 0.00 / yr | $419K |
| Wildfire | Very Low | 0.00 / yr | $45K |
| Strong Wind | Low | 5.20 / yr | $389K |
| Winter Weather | Low | 5.32 / yr | $42K |
| Lightning | Low | 53.96 / yr | $134K |
| Tornado | Low | 0.07 / yr | $628K |
| Cold Wave | Low | 0.74 / yr | $435K |
| Ice Storm | Low | 0.31 / yr | $26K |
| Hail | Very Low | 2.99 / yr | $93K |
| Riverine Flood | Very Low | 0.61 / yr | $3M |
| Hurricane | Very Low | 0.01 / yr | $7K |
| Heat Wave | Very Low | 0.47 / yr | $21K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Drought | Very Low | 15.57 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Union County has received 16 federal disaster declarations since 1973, most recently Severe Winter Storm in February 2026. Most frequent causes: Severe Storm (7), Flood (3), Winter Storm (2).
| Declared | Type | Disaster |
|---|---|---|
| February 2026 | Winter Storm | Severe Winter Storm |
| January 2026 | Winter Storm | Severe Winter Storm |
| April 2025 | Severe Storm | Severe Storms, Straight-Line Winds, Tornadoes, and Flooding |
| April 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| April 2019 | Flood | Severe Storms, Flooding, Landslides, and Mudslides |
| March 2011 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
| September 2005 | Hurricane | Hurricane Katrina Evacuation |
| March 2003 | Severe Storm | Severe Storms and Flooding |
| August 2001 | Severe Storm | Severe Storms and Flooding |
Showing the 10 most recent of 16 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Union County?
Union County has a composite FEMA National Risk Index score of 12.9 out of 100, placing it in the Very Low category and the 13th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Union County?
The three highest-rated hazards are Landslide (Medium, $43K EAL), Earthquake (Low, $419K EAL), Wildfire (Very Low, $45K EAL). These account for most of the county's expected annual losses.
How does Union County compare to other Tennessee counties?
Union County ranks #88 of 95 Tennessee counties for overall natural disaster risk, with a very low rating.
How many federally declared disasters has Union County had?
FEMA records 16 federal disaster declarations for Union County since 1973, most often 7 for severe storm events and 3 for flood events. The most recent was Severe Winter Storm, declared in February 2026.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Union County's $5M EAL is a statistical average, not a guarantee for any specific year or address.