65 flood insurance claims·$263,679 paid
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 Knox County, Ohio. 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 summer thunderstorms dominates the flood character of Knox County, accounting for 20 of the 31 recorded flood events over the last 30 years alongside 11 standard flood events.
Recent weather patterns illustrate these risks. On July 3, 2019, multiple rounds of storms dropped 1.5 to 2.5 inches of rain across Knox County. Later, on May 18, 2020, slow-moving storms produced rain rates of 2 inches an hour or higher with storms that repeated over the same areas, and a warm front brought further elevated thunderstorms on March 28, 2020.
National Flood Insurance Program records show claims across multiple zones with varying impacts. Zone A accounts for 35 claims with an average payout of $4,065 and an average recorded water depth of 14 inches. Meanwhile, Zone X recorded 11 claims with an average payout of $10,037 and an average water depth of 2 inches; Zone X unshaded recorded 9 claims with an average payout of $10,431 and an average water depth of 9 inches; Zone X shaded recorded 4 claims with an average payout of $11,596 and an average water depth of 0 inches; and Zone unknown recorded 6 claims with an average payout of $929 and an average water depth of 1 inch. Property owners in Zone A should pay the most attention, given the higher frequency of claims and deeper average water depths associated with those locations.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
27% of Knox County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
48 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 8 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 1998, with 22 claims and $63,969 paid, the year of Severe Storms, Flooding, and Tornadoes.
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.
13 NOAA storm reports from Knox County describe what happened, in the words of the forecasters who covered it. Read the Ohio flood stories →
13 federal disaster declarations since 1977.
| Disaster | Began |
|---|---|
| Severe Storms | Jun 29, 2012 |
| Severe Storms And Straight-line Winds | Jun 29, 2012 |
| Severe Wind Storm Associated With Tropical Depression Ike | Sep 14, 2008 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Severe Winter Storms, Flooding, And Mudslides | Dec 22, 2004 |
| Severe Storms And Flooding | Aug 27, 2004 |
| Severe Storms And Flooding | May 18, 2004 |
| Power Outage | Aug 14, 2003 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
31 since 1996: 20 flash floods and 11 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jun 5, 2024 | — |
| Flood | Mar 28, 2020 | — |
| Flood | May 18, 2020 | — |
| Flash Flood | Jul 3, 2019 | $2,000 |
| Flood | Feb 15, 2018 | $25,000 |
| Flood | Apr 3, 2018 | $4,000 |
| Flood | Nov 18, 2017 | $50,000 |
| Flash Flood | Jun 13, 2017 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jun 5, 2024. Knox County resided in the warm and moist sector during the early through late evening of the 5th as a cold front swept eastward from northwestern IN and the Lower Ohio Valley to far-western OH and far-southeastern IN. Ahead of the cold front, scattered thunderstorms, including supercells, developed along a surface trough axis and resided in an environment favorable for tornadic supercells. This environment was co…
Flood · Mar 28, 2020. A warm front over central Ohio on the morning of Saturday March 28, 2020 was the focus for several rounds of elevated thunderstorms through the early afternoon hours. The main area for these thunderstorms were the US 30 and I-76 corridors through the morning and early afternoon hours as storms remained parallel to the warm front and moved with the 850 mb jet. These storms well utilized the steep mid-level lapse ra…
Flood · May 18, 2020. A slow moving upper low over Illinois combined with a conveyor belt of humid air over Ohio supported widespread showers and thunderstorms over southern and central Ohio on the afternoon and evening of the 18th. The weather conditions supported not severe weather but heavy rain. Rain rates of 2 inches an hour or higher were observed with storms that trained, or repeated over the same areas. Overnight the low sank…
Flash Flood · Jul 3, 2019. Multiple rounds of showers and thunderstorms moved across central Ohio in the afternoon and evening of July 2nd. By the early morning hours of July 3, a third round of showers moved along the US 30 corridor mainly over Marion, Morrow, Knox and counties further south. Rainfall of 1.5 to 2.5 inches across Marion, Morrow, and Knox Counties.
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 Knox 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.