40 flood insurance claims·$362,051 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 Knox County, Illinois. 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 profile of Knox County, Illinois, accounting for 34 out of 45 recorded flood events over the last thirty years, alongside 11 standard flood events.
Recent occurrences illustrate this hazard, such as the slow-moving cold front on June 6, 2022, which dropped 1 to 3 inches of rain in a short period and focused localized flash flooding along and north of an Abingdon to Lacon line. Similarly, a weak low-pressure system and stationary front produced isolated flash flooding across the area on July 8, 2022.
National Flood Insurance Program records show that flood impacts affect properties across multiple zones. Zone A has accumulated 19 claims with an average payout of $18,337 and an average recorded water depth of 23 inches. Meanwhile, Zone X properties have recorded 9 claims averaging $14,044 with an average water depth of 8 inches, and a single claim in Zone X_UNSHADED recorded an average water depth of 26 inches with an $8,612 payout. Zone UNKNOWN accounts for 11 claims with an average payout of $1,557 and an average water depth of 2 inches. Homeowners, real estate agents, and journalists should pay the closest attention to properties located within designated Zone A and other flood-prone areas where significant standing water depths have historically been documented.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
5% of Knox County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
20 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 15 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 2013, with 9 claims and $165,522 paid, the year of Severe Storms, Straight-line Winds, and Flooding.
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 Illinois flood stories →
11 federal disaster declarations since 1974, 4 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms And Flooding | Feb 24, 2019 |
| Severe Storms, Straight-line Winds, And Flooding | Apr 16, 2013 |
| Severe Winter Storm And Snowstorm | Jan 31, 2011 |
| Severe Storms And Flooding | Aug 20, 2007 |
| Snow | Nov 30, 2006 |
| Hurricane Katrina Evacuation | Aug 29, 2005 |
| Winter Storm 1/1/99 | Jan 1, 1999 |
| Severe Storms & Flooding | Apr 13, 1993 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
45 since 1996: 34 flash floods and 11 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Jul 8, 2022 | — |
| Flash Flood | Jun 6, 2022 | — |
| Flash Flood | May 28, 2019 | — |
| Flash Flood | Sep 7, 2018 | — |
| Flash Flood | Oct 14, 2017 | — |
| Flash Flood | Jul 16, 2015 | — |
| Flash Flood | Jun 14, 2015 | — |
| Flash Flood | Jul 11, 2015 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Jul 8, 2022. A weak low pressure system was located in southwestern Illinois on the afternoon of July 8, 2022, with a stationary front draped near the I-70 corridor. A secondary cold front pushed into central Illinois from the north, and scattered thunderstorms developed along both boundaries. As storm clusters progressed to the southeast, they produced isolated flash flooding, hail, and wind damage.
Flash Flood · Jun 6, 2022. A slow-moving cold front interacted with a warm and moist environment to trigger clusters of thunderstorms across north-central Illinois during the late afternoon and evening of June 6th. Some of the storms produced rainfall of 1 to 3 inches in a short period of time, leading to localized flash flooding. The flooding was primarily focused along and north of an Abingdon to Lacon line.
Flash Flood · May 28, 2019. An upper-level disturbance tracking along a nearly stationary frontal boundary triggered a line of strong to severe thunderstorms across west-central Illinois during the late evening of May 28th. The storms tracked eastward and gradually weakened as they approached the I-55 corridor by the early morning of May 29th. Wind gusts of 60-70 mph downed numerous tree branches and power lines as the storms advanced east…
Flash Flood · Sep 7, 2018. Heavy rain impacted central and southeast Illinois as the remnants of Tropical Storm Gordon tracked from Arkansas during the afternoon of September 7th to southern Ohio by the afternoon of September 9th. The rainfall was further enhanced by a weak cold front dropping southward out of the Upper Midwest. Rainfall was heaviest south of I-70 in closer proximity to the track of the storm, with amounts ranging from 5…
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.