51 flood insurance claims·$2.2M paid·4 federal flood & hurricane disasters
Share of the whole county outline, rivers and lakes included; parts FEMA hasn’t mapped count as zero.
Shaded areas are FEMA’s mapped flood hazard zones in and around Johnson County, Tennessee. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.
Flash flooding from severe weather systems and heavy rainfall dominates the flood profile of Johnson County, Tennessee, accounting for 17 of the 27 recorded flood events over the last 30 years alongside 9 general floods and 1 tropical storm event.
Recent historic impacts include catastrophic flash flooding and river flooding in September 2024 from Tropical Storm Helene, which capped off a multi-day heavy rainfall event driven by a stalled upper low. Additional flash flooding occurred in February 2022 from a stalled cold front combined with a moving surface low, and in August 2022 from slow-moving thunderstorms driven by weak steering currents.
Property owners in FEMA flood zones should assess their specific risk based on historical claims data. Zone A properties experienced 31 claims with an average payout of $52,405 and an average recorded water depth of 2 inches. Zone X properties recorded 11 claims with an average payout of $53,369 and an average water depth of 45 inches. Unshaded Zone X properties saw 7 claims averaging $16,575 with an average water depth of 2 inches, while properties with unknown zones recorded 2 claims averaging $5,132 with an average water depth of 1 inch. Homeowners, real estate agents, and journalists should pay particular attention to properties located within mapped high-risk riverine areas (Zone A) and those subject to localized pooling or intense storm water accumulation (Zone X).
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
18% of Johnson County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
38 NFIP claims with a recorded rated flood zone, 1978 to date. The zone is the one FEMA used to rate that policy, which may not match today’s map. Source: OpenFEMA NFIP claims.
In flood insurance claims here that reported a flood depth, the average was 14 inches.
Drawn to scale against an 80-inch door. Even a few inches soaks flooring, the bottom of the drywall and anything plugged in near the floor.
Average of the depths reported on claims (zero and implausible values left out); FEMA’s record doesn’t say exactly where each depth was measured. Source: OpenFEMA NFIP claims.
The worst year was 2024, with 33 claims and $1.9M paid, the year of Tropical Storm Helene.
Bar height is scaled by square root so ordinary years stay visible next to the worst one. NFIP claims by year of loss. Source: OpenFEMA.
4 NOAA storm reports from Johnson County describe what happened, in the words of the forecasters who covered it. Read the Tennessee flood stories →
20 federal disaster declarations since 1973, 4 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Winter Storm | Jan 22, 2026 |
| Severe Storms, Straight-line Winds, Tornadoes, And Flooding | Apr 2, 2025 |
| Tropical Storm Helene | Sep 26, 2024 |
| Severe Storms, Straight-line Winds, And Tornadoes | Mar 31, 2023 |
| Severe Storms, Flooding, Landslides, And Mudslides | Feb 19, 2019 |
| Severe Storms, Tornadoes, Straight-line Winds, And Associated Flooding | Apr 25, 2011 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Severe Storms And Flooding | Sep 16, 2004 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
27 since 1996: 17 flash floods and 9 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Sep 27, 2024 | $6.5M · 1 killed |
| Flash Flood | Sep 25, 2024 | — |
| Flash Flood | Feb 24, 2022 | — |
| Flash Flood | Aug 10, 2022 | — |
| Flash Flood | Mar 28, 2021 | — |
| Flood | Nov 12, 2020 | — |
| Flood | Feb 23, 2019 | $900,000 |
| Flood | Jan 15, 2013 | $1,000 |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Sep 27, 2024. Tropical Storm Helene caps off a several day heavy rainfall event in association with a stalled closed upper low that drew a stream of tropical moisture into the area on the 25th and 26th. The arrival of Helene on the 27th yielded catastrophic flash flooding and river flooding, as well as significant wind damage as wet soils and strong wind gusts led to forest damage.
Flash Flood · Sep 25, 2024. Tropical Storm Helene caps off a several day heavy rainfall event in association with a stalled closed upper low that drew a stream of tropical moisture into the area on the 25th and 26th. The arrival of Helene on the 27th yielded catastrophic flash flooding and river flooding, as well as significant wind damage as wet soils and strong wind gusts led to forest damage.
Flash Flood · Feb 24, 2022. A moist southwesterly flow aloft ran nearly parallel to a stalled cold front near east Tennessee on the 23rd. A surface low near Lake Charles LA would move up the boundary and produce a second round of rains on the 24th.
Flash Flood · Aug 10, 2022. High pressure over the area led to weak steering currents. Slow moving thunderstorms produced locally heavy rain.
National Weather Service narratives, lightly trimmed. Source: NOAA Storm Events Database.
Every colour on the map above is a place on this drawing: where the ground sits relative to the flood FEMA plans for.
If a building in Johnson County is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.
Outside those zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Since Risk Rating 2.0, NFIP premiums are set for each building, so the only reliable price is a quote: FloodSmart.gov or a local agent.