Williamson County, Tennessee: hazard history
What federal records show has already happened here: disaster declarations, storms, and flood insurance claims. This is a record of the past. It is not a forecast and not a hazard score.
At a glance
What this means
- The event NOAA recorded most often here is Thunderstorm Wind, with 399 records.
- The costliest single record is Flood in 2010: $10.0M in property damage, in the dollars of that year.
- The deadliest record is Thunderstorm Wind in 2003, with 1 death.
- FEMA has declared 16 disasters that named this county, most often for severe storm.
- The worst year for flood insurance claims was 2010, with 431 claims.
What this can't tell you
- What happens next. Past events do not set the odds of the next one.
- Anything before 1996 from NOAA. That is when NOAA began recording every event type; earlier files hold only tornado, hail and wind, so they are left out on purpose.
- Today's cost. Damage and payments are in the dollars of the year they happened.
- A flood rate. NFIP counts claims but not how many homes were insured, and many flooded homes carry no flood insurance.
- Earthquakes, wildfire perimeters or radar-detected hail. Those records are not tied to counties.
Federal disaster declarations (FEMA)
FEMA declared 16 disasters that named Williamson County between 1974 and 2026.
| Incident type | Disasters | Most recent |
|---|---|---|
| Severe Storm | 8 | 2025 |
| Biological | 2 | 2020 |
| Tornado | 2 | 2021 |
| Winter Storm | 2 | 2026 |
| Flood | 1 | 1975 |
| Hurricane | 1 | 2005 |
Most recent declarations
- DR-4898 2026 · Winter Storm · Severe Winter Storm
- EM-3635 2026 · Winter Storm · Severe Winter Storm
- EM-3625 2025 · Severe Storm · Severe Storms, Straight-line Winds, Tornadoes, And Flooding
- DR-4601 2021 · Tornado · Severe Storms, Tornadoes, And Flooding
- EM-3473 2020 · Biological · Covid-19
- DR-4514 2020 · Biological · Covid-19 Pandemic
- DR-1909 2010 · Severe Storm · Severe Storms, Flooding, Straight-line Winds, And Tornadoes
- DR-1745 2008 · Severe Storm · Severe Storms, Tornadoes, Straight-line Winds, And Flooding
- EM-3217 2005 · Hurricane · Hurricane Katrina Evacuation
- DR-1464 2003 · Severe Storm · Severe Storms, Tornadoes, And Flooding
Not counted above: 1 statewide declarations, which covered every county in Tennessee. A declaration is a decision to send federal help, not a measure of how bad an event was. Records run from 1953. Source: FEMA OpenFEMA Disaster Declarations Summaries.
Storms recorded by NOAA, by type
| Event type | Records | Deaths | Injuries | Property damage |
|---|---|---|---|---|
| Thunderstorm Wind | 399 | 4 | 0 | $3.2M |
| Hail | 184 | 0 | 0 | $110K |
| Flash Flood | 73 | 1 | 0 | $2.4M |
| Winter Weather | 44 | 0 | 0 | $39K |
| Lightning | 31 | 0 | 2 | $2.9M |
| Drought | 29 | 0 | 0 | $0 |
| Flood | 24 | 0 | 0 | $10.0M |
| Tornado | 19 | 0 | 7 | $13.2M |
| Winter Storm | 17 | 0 | 0 | $100K |
| Strong Wind | 9 | 0 | 0 | $33K |
| Funnel Cloud | 8 | 0 | 0 | $0 |
| Heavy Snow | 8 | 0 | 0 | $0 |
| High Wind | 7 | 0 | 0 | $1.1M |
| Heavy Rain | 5 | 0 | 0 | $0 |
| Excessive Heat | 4 | 0 | 0 | $0 |
| Ice Storm | 2 | 0 | 0 | $25K |
| Extreme Cold/Wind Chill | 1 | 0 | 0 | $0 |
Records start in 1996. Damage is NOAA's estimate at the time, in nominal dollars, and is often rounded; it is not insurance claims data. A storm that crossed two NOAA zones in this county is recorded, and counted, once per zone. A storm filed against a forecast zone is counted in every county that zone covers, with the whole storm's damage; do not add these figures across counties.
Year by year
NOAA storm event records in Williamson County each year. The busiest year was 2025, with 75 records.
Show the numbers for every year
| Year | Records | Deaths | Property damage |
|---|---|---|---|
| 1996 | 11 | 0 | $11K |
| 1997 | 27 | 0 | $160K |
| 1998 | 10 | 0 | $81K |
| 1999 | 6 | 0 | $507K |
| 2000 | 13 | 0 | $100K |
| 2001 | 17 | 0 | $25K |
| 2002 | 11 | 0 | $0 |
| 2003 | 35 | 1 | $5.5M |
| 2004 | 13 | 0 | $11K |
| 2005 | 14 | 0 | $20K |
| 2006 | 18 | 0 | $1K |
| 2007 | 15 | 0 | $7K |
| 2008 | 10 | 0 | $261K |
| 2009 | 13 | 0 | $76K |
| 2010 | 28 | 1 | $12.1M |
| 2011 | 18 | 1 | $145K |
| 2012 | 51 | 0 | $381K |
| 2013 | 57 | 0 | $541K |
| 2014 | 33 | 0 | $129K |
| 2015 | 30 | 0 | $178K |
| 2016 | 53 | 0 | $140K |
| 2017 | 56 | 0 | $7.5M |
| 2018 | 25 | 0 | $99K |
| 2019 | 35 | 0 | $225K |
| 2020 | 29 | 1 | $1.1M |
| 2021 | 29 | 0 | $1.5M |
| 2022 | 40 | 1 | $127K |
| 2023 | 48 | 0 | $1.4M |
| 2024 | 37 | 0 | $471K |
| 2025 | 75 | 0 | $177K |
| 2026 | 7 | 0 | $18K |
Years with no record are left out of the table, not shown as zero.
Notable events
Costliest records
- Flood · May 2, 2010$10.0MNOAA name: Williamson County · NOAA record 226270
- Tornado · Mar 1, 2017$7.3MNOAA name: Williamson County · NOAA record 683870
- Tornado · May 5, 2003$3.0MNOAA name: Williamson County · NOAA record 5357335
- Tornado · May 11, 2003$2.2MNOAA name: Williamson County · 1 injury · NOAA record 5357401
- Lightning · Oct 24, 2010$1.8MNOAA name: Williamson County · NOAA record 261587
Deadliest records
- Thunderstorm Wind · Jun 11, 20031 deathNOAA name: Williamson County · NOAA record 5362954
- Flash Flood · May 1, 20101 deathNOAA name: Williamson County · $50K damage · NOAA record 233431
- Thunderstorm Wind · Apr 27, 20111 deathNOAA name: Williamson County · NOAA record 303128
- Thunderstorm Wind · May 3, 20201 deathNOAA name: Williamson County · NOAA record 897267
- Thunderstorm Wind · Oct 12, 20221 deathNOAA name: Williamson County · $10K damage · NOAA record 1056119
Each line is one NOAA record, linked to its page at NOAA. One large storm can appear more than once if NOAA recorded it in several zones of this county. Dollars are nominal.
Flood insurance claims (NFIP)
The National Flood Insurance Program paid $29.5M on 1,073 claims in Williamson County from 1978 to 2024.
| Year | Claims | Paid |
|---|---|---|
| 2010 | 431 | $16.9M |
| 2021 | 198 | $8.2M |
| 2003 | 54 | $584K |
| 1979 | 46 | $209K |
| 1998 | 36 | $231K |
A count of claims, not a rate: NFIP publishes no count of insured homes beside it, and most flood damage is uninsured. Nominal dollars. Records run from 1978 to 2024; claims filed without a county code are not on any county page. Source: FEMA OpenFEMA FIMA NFIP Redacted Claims.
Hazard vulnerability analysis: the probability column for a facility in Williamson County
A hazard vulnerability analysis rates each hazard for probability, impact, preparedness and response. Probability is the one column the county’s federal record can fill — NCEI storm events from 1996 to 2026 and FEMA declarations naming the county — and this is what it says for a facility here, on the 0–3 scale of the all-hazards structure surveyors expect. The other six columns are the facility’s own judgment about its building, and Calchis leaves them blank.
| Hazard | Prob. | Basis, from the county record |
|---|---|---|
| Severe Thunderstorm | 3 | 614 NCEI events over 31 years (19.81/yr). 8 federal disaster declarations naming the county. |
| Flood, External | 3 | 102 NCEI events over 31 years (3.29/yr). 1 federal disaster declaration naming the county. |
| Snow Fall / Blizzard / Ice Storm | 3 | 71 NCEI events over 31 years (2.29/yr). No federal disaster declaration of this kind has named the county. |
| Hurricane / Tropical Storm | 2 | No events of this kind on the county's NCEI record over 31 years. 1 federal disaster declaration naming the county. |
| Tornado | 2 | 19 NCEI events over 31 years (0.61/yr). 2 federal disaster declarations naming the county. |
| Temperature Extremes | 2 | 5 NCEI events over 31 years (0.16/yr). No federal disaster declaration of this kind has named the county. |
| Drought | 2 | 29 NCEI events over 31 years (0.94/yr). No federal disaster declaration of this kind has named the county. |
| High Wind (non-convective) | 2 | 16 NCEI events over 31 years (0.52/yr). No federal disaster declaration of this kind has named the county. |
| Epidemic | 2 | 2 federal disaster declarations naming the county. |
| Wild Fire | 1 | No events of this kind on the county's NCEI record over 31 years. No federal disaster declaration of this kind has named the county. |
| Earthquake | 1 | No federal disaster declaration of this kind has named the county. |
| Landslide | 1 | No events of this kind on the county's NCEI record over 31 years. No federal disaster declaration of this kind has named the county. |
| Tidal Wave / Tsunami | 1 | No events of this kind on the county's NCEI record over 31 years. No federal disaster declaration of this kind has named the county. |
| Volcano | 1 | No events of this kind on the county's NCEI record over 31 years. No federal disaster declaration of this kind has named the county. |
| Dam Inundation | 1 | No federal disaster declaration of this kind has named the county. |
A dash means the record does not speak to that hazard; it is not a zero. Whether a finished document satisfies the CMS Emergency Preparedness Rule is the facility’s finding and its surveyor’s. Complete the HVA for a facility in Williamson County — the technological, human and hazardous-materials rows, the six facility columns, the approval and the printed document — or read the sample analysis on that page first.
How this page was made
- Every figure is counted from public federal records held by Calchis: NOAA NCEI Storm Events, FEMA OpenFEMA Disaster Declarations, and FEMA NFIP claims. Nothing is modeled or estimated.
- NOAA files some events against a county and others against an NWS forecast zone, and publishes a code for both. Records are counted as Williamson County by that code — county records by the county's own FIPS code, zone records through the National Weather Service's published list of which counties each zone covers. No name matching is involved. Of 864 records, 739 were filed against this county and 125 against a forecast zone covering it. A zone storm is counted in every county its zone covers, and its damage figure is the whole storm's, not this county's share — NOAA does not publish that split. So these figures describe this county; they must not be added up across counties.
- Counts last rebuilt from the source records on Sep 15, 2026.
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Recorded history from federal public records. Not a hazard score, a risk score, or a forecast, and not a substitute for professional actuarial or emergency-management assessment. Decision-support intelligence — not a primary alerting or dispatch system. Verify against official sources.