Williamson County, TN Environment & Hazard Risk
Relatively Moderate natural hazard risk, led by cold wave. 877 storm events since 1996.
- Expected yearly loss
- $98.02M
- Relatively Moderate nationally
- Storm events since 1996
- 877
- Most often thunderstorm wind
- Flood insurance policies
- 1,284
- 2.4% of homes
- Hurricanes nearby
- 0
- 2 tropical storms or stronger since 1934
Natural hazard risk
FEMA National Risk Index, December 2025
Overall risk
Relatively Moderate
Score 85.1 of 100
Social vulnerability
Very Low
Score 10.6 of 100
Community resilience
Very High
Score 95.2 of 100
Community resilience runs the other way: a higher rating means a community can recover faster.
Building value exposed: $61.39B · Agriculture value exposed: $39.79M · Risk-adjusted yearly loss: $58.71M
Risk by hazard
- Cold waveRelatively High$13.41M/yr expected annual loss, about 1.2 events a year
- EarthquakeRelatively Low$8.48M/yr expected annual loss, about once every 298 years
- Strong windRelatively High$3.37M/yr expected annual loss, about 6.1 events a year
- TornadoRelatively Moderate$11.55M/yr expected annual loss, about once every 2 years
- Winter weatherRelatively Moderate$469K/yr expected annual loss, about 5.2 events a year
- Ice stormRelatively High$1.01M/yr expected annual loss, about once every 2 years
- Heat waveRelatively Low$1.78M/yr expected annual loss, about 4.9 events a year
- LandslideVery Low$3,157/yr expected annual loss, about once every 1 year
- LightningRelatively Low$468K/yr expected annual loss, about 61 events a year
- HailRelatively Low$332K/yr expected annual loss, about 3.5 events a year
- HurricaneVery Low$55.4K/yr expected annual loss, about once every 62 years
- WildfireVery Low$44.66K/yr expected annual loss, about once every 21,258 years
- DroughtRelatively Low$77.21K/yr expected annual loss, about 9.6 events a year
Bars show the national percentile score (0 to 100) for each hazard. Dollar figures are expected annual losses to buildings, people and crops. Not rated here: avalanche, coastal flooding, riverine flooding, tsunami, volcanic activity.
Flood risk and insurance
National Flood Insurance Program and FEMA flood maps
Check the flood zone for an address
- Homes with flood insurance
- 1,284 of 53,519 (2.4%)
- Homes in high-risk flood zones
- 796
- Insured in high-risk zones
- 687 (86%)
- Flood claims since 1978
- 1,103
- Claims paid since 1978
- $31.07M
Flood claims paid per year
- Late spring storms$18.17M · 431 claims
- Heavy rains$426K · 44 claims
- Central U.S. April Flooding$84.54K · 4 claims
- Tennessee Flooding$26.4K · 1 claim
- Flooding$26.05K · 7 claims
- Early winter storms$5,872 · 1 claim
Storm history
Since 1996: 877 events, 7 deaths, $33.25M in damage
- Thunderstorm Wind404 · 6 deaths
- Hail184
- Flash Flood80 · 1 death
- Winter Weather44
- Lightning31
- Drought29
- Flood25
- Tornado19
- Winter Storm17
- Strong Wind9
Events per year
26 tornadoes on record (EF0 11, EF1 1, EF2 1, F0 4, F1 6, F3 2, F4 1).
Most damaging storms
Since 1996, ranked by deaths, injuries and damage
- Thunderstorm Wind43 kt wind07/20/2026
Mudsink, Williamson County
2 deaths, $20K damage
What happened
A tree fell onto a vehicle during a strong thunderstorm in Franklin. Unfortunately, the two occupants in the vehicle were killed while traveling on Carothers Parkway near South Carothers Road. Very heavy rain was occurring at the time, and Tennessee Highway Patrol reported that the tree was rotted.
- Flash Flood05/01/2010
Peytonsville, Williamson County
1 death, $51K damage
What happened
Flash flooding was reported along Peytonsville Road. Portions of Peytonsville Road had fallen into a nearby creek. Also, a fatality occurred when a man drove his vehicle into Garrison Creek at 12:30 PM CST.
- Thunderstorm Wind50 kt wind10/12/2022
Forest Home, Williamson County
1 death, $10K damage
What happened
Strong thunderstorm winds downed a tree onto a vehicle on Old Natchez Trace northwest of Franklin. A 22-year-old woman who was driving at the time was killed.
- Flood05/02/2010
Nolensville, Williamson County
$10M damage
What happened
Nolensville road, south of Nashville, was flooded. Some cars were left abandoned. Details concerning amount of damage to cars abandoned were unknown. Also, numerous homes, numerous businesses, numerous non comercial buildings, along with several county, state, and federal roads across the county received damage due to the flood.
- Thunderstorm Wind56 kt wind05/03/2020
Harpeth, Williamson County
1 death
What happened
A tree fell onto and killed a man near Bethesda Road at Highway 431 who was outside playing with his daughter along a creek.
- Thunderstorm Wind55 kt wind04/27/2011
Mudsink, Williamson County
1 death
What happened
A woman was struck in the head by a fallen tree limb and then died 24 hours later.
Latest storm reports
Newest first
- Flash Flood07/22/2026
Berrys Chapel, Williamson County
- Flash Flood07/20/2026
Mallorys, Williamson County
- Thunderstorm Wind43 kt wind07/20/2026
Mudsink, Williamson County
2 deaths, $20K damage
- Flash Flood07/17/2026
Mallorys, Williamson County
- Flash Flood07/17/2026
Mudsink, Williamson County
- Flash Flood07/08/2026
Mallorys, Williamson County
$50K damage
- Flood07/04/2026
Mallorys, Williamson County
- Flash Flood07/03/2026
Mallorys, Williamson County
Hurricanes and tropical storms
Storms whose track crossed Williamson County, with the wind when it passed
- Hurricane Audrey (1957)06/24/1957 · Landfall: LA · 946 mbTropical storm40 mph nearby
- Unnamed storm (1934)06/04/1934 · Landfall: LA · 966 mbTropical storm40 mph nearby
Drinking water
7 community water systems serve about 252,925 people. Violations since 2021.
1 system had health-based violations, such as a contaminant over the legal limit or a missed treatment step. 1 system had a violation of any kind still open at last report.
- Franklin Water DeptServes 77,222 · Surface water · Local government3 health violations+4 monitoring or reporting
- H.b.& T.s. Utility DistrictServes 40,094 · Purchased surface water · Local governmentNo health violations+3 monitoring or reporting
- Milcrofton Utility DistrictServes 38,032 · Purchased surface water · Local governmentNo health violations
- Nolensville-College Grove U.d.Serves 34,159 · Purchased surface water · Local governmentNo health violations
- Mallory Valley U.d.Serves 31,703 · Purchased surface water · Local governmentNo health violations+1 monitoring or reporting
- Brentwood Water DepartmentServes 30,645 · Purchased surface water · Local governmentNo health violations
- Gateway Utility Company, INC.Serves 1,070 · Purchased surface water · PrivateNo health violations+4 monitoring or reporting
Largest systems by population served. Monitoring and reporting violations mean required tests or notices were late or missing, not that the water was unsafe.
Climate
1991-2020 normals at Franklin Sewage Plt, 5.2 mi from the county center
Summer highs peak around 91°F in Jul and winter lows bottom out near 29°F in Jan. About 53.8 inches of rain falls in a typical year, with 1.7 inches of snow.
| Month | High | Low | Rain | Snow |
|---|---|---|---|---|
| Jan | 49°F | 29°F | 4.25 in | 0.9 in |
| Feb | 53°F | 31°F | 4.76 in | 0.3 in |
| Mar | 62°F | 38°F | 5.16 in | 0.4 in |
| Apr | 72°F | 46°F | 5.16 in | - |
| May | 80°F | 55°F | 5.39 in | - |
| Jun | 87°F | 64°F | 4.39 in | - |
| Jul | 91°F | 69°F | 4.57 in | - |
| Aug | 90°F | 67°F | 3.61 in | - |
| Sep | 85°F | 60°F | 4.00 in | - |
| Oct | 74°F | 47°F | 3.47 in | - |
| Nov | 62°F | 37°F | 3.83 in | - |
| Dec | 53°F | 32°F | 5.20 in | 0.1 in |
| Year | 60°F average | 53.8 in | 1.7 in | |
Pollution sites
0 Superfund sites and 5 toxic release facilities in Williamson County
Superfund sites
None in this county.
Toxic release facilities
- Essex Solutions USA LLC40,856 lbs released, Franklin
- Apcom Inc30,291 lbs released, Franklin
- Foley Products Co - Franklinunder 1 lb released, Franklin
- Georgia Masonry Supply Franklin0 lbs released, Franklin
- Smyrna Ready Mix LLC Plant 50 lbs released, Franklin
Total: 71,147 lbs in 2024, 40,854 lbs to air.
Superfund sitesToxic release facilitiesEPA inspections and enforcementAir toxics cancer risk95 historic places
Frequently asked questions
- How risky is Williamson County for natural disasters?
- FEMA rates Williamson County relatively moderate for overall natural hazard risk, with expected losses of $98.02M a year. The highest-rated hazards are cold wave (relatively high), earthquake (relatively low), strong wind (relatively high).
- What storms are most common in Williamson County?
- Since 1996, NOAA recorded 877 storm events affecting Williamson County, most often thunderstorm wind (404), hail (184), flash flood (80).
- How many tornadoes have hit Williamson County?
- 26 tornadoes have been recorded in Williamson County since 1950, including 3 rated F3/EF3 or stronger.
- How many homes in Williamson County have flood insurance?
- 1,284 residential flood insurance policies are in force in Williamson County, covering about 2.4% of homes. The program has paid $31.07M on 1,103 claims here since 1978.
- What is the weather like in Williamson County?
- At Franklin Sewage Plt, average highs reach 91°F in Jul and lows fall to 29°F in Jan, with 53.8 inches of rain a year (1991-2020 normals).
Source: FEMA (National Risk Index, NFIP), NOAA (Storm Events, HURDAT2, Climate Normals), EPA · Last updated 08/01/2026 · Storm counts include events in forecast zones that touch the county. This product uses the FEMA OpenFEMA API, but is not endorsed by FEMA.