12,031 flood insurance claims·$264.6M paid·10 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 St. Louis County, Missouri. 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 slow-moving summer thunderstorms and heavy rainfall events dominates the flood risk in St. Louis County. Over the last 30 years, the NOAA Storm Events Database recorded 68 flash flood events resulting in 7 deaths, alongside 21 general flood events. Recent events illustrate this hazard: on August 10, 2025, slow-moving thunderstorms caused flash flooding that covered Interstates 44, 55, 64, 70, and 255 with water. Additionally, a stationary front brought heavy rainfall on April 4 and 5, 2025, leaving numerous metropolitan roads impassable.
National Flood Insurance Program claims data demonstrates that flood risks extend beyond high-risk zones. Zone A carries the heaviest burden with 9,457 claims averaging a $27,145 payout and an average recorded water depth of 10 inches. However, properties in moderate-to-low risk areas also experience significant impacts. Zone X recorded 793 claims with an average payout of $42,246 and an average recorded water depth of 17 inches, while Zone X_SHADED saw 473 claims averaging $37,589 with an average recorded water depth of 5 inches. Homeowners and real estate agents in both designated high-risk zones and shaded Zone X areas should pay close attention to these historical payout and water depth averages when evaluating property risk.
Summary written from NOAA storm reports and NFIP claims for this county. Not a prediction.
9% of St. Louis County’s flood insurance claims were on properties rated outside FEMA’s high-risk zones.
10,446 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 9 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 1993, with 1,967 claims and $51.1M paid, the year of Severe Storms & Flooding and Severe Storms, Tornadoes, 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.
22 NOAA storm reports from St. Louis County describe what happened, in the words of the forecasters who covered it. Read the Missouri flood stories →
34 federal disaster declarations since 1973, 10 of them floods, coastal storms or hurricanes.
| Disaster | Began |
|---|---|
| Severe Storms, Straight-line Winds, Tornadoes, And Flooding | May 16, 2025 |
| Severe Storms, Straight-line Winds, Tornadoes, And Wildfires | Mar 14, 2025 |
| Severe Storms And Flooding | Jul 25, 2022 |
| Severe Storms, Tornadoes, Straight-line Winds And Flooding | Apr 28, 2017 |
| Severe Storms, Tornadoes, Straight-line Winds, And Flooding | Dec 23, 2015 |
| Severe Storms, Straight-line Winds, Tornadoes, And Flooding | May 29, 2013 |
| Flooding | Jun 1, 2011 |
| Severe Storms, Tornadoes, And Flooding | Apr 19, 2011 |
Weather and water disasters only; most recent first. Source: OpenFEMA Disaster Declarations.
89 since 1996: 68 flash floods and 21 river or area floods.
| Event | Date | Damage |
|---|---|---|
| Flash Flood | Aug 10, 2025 | $1,000 |
| Flood | Apr 5, 2025 | $200,000 |
| Flash Flood | Apr 4, 2025 | $30,000 |
| Flood | Apr 4, 2025 | — |
| Flash Flood | Nov 4, 2024 | $200,000 · 2 killed |
| Flood | Nov 4, 2024 | $50,000 |
| Flash Flood | Apr 2, 2024 | $1,000 |
| Flash Flood | Jul 17, 2023 | — |
— = no damage estimate in the record. Source: NOAA Storm Events Database.
Flash Flood · Aug 10, 2025. Conditions were primed for flash flooding during the afternoon of August 10th. With very little wind shear, very high precipitable water values, and an area of moisture convergence, thunderstorms were able to develop and move very slowly as they poured out. This is what happened over the St. Louis metropolitan area. Flash flooding occurred as a result, with Interstates 44, 55, 64, 70, and 255 all suffering from wa…
Flood · Apr 5, 2025. A stationary front over southern Missouri along with ample mid-level forcing, moisture, and efficient rain processes resulted in flooding across portions of east-central and southeast Missouri. Numerous roads across the St. Louis metropolitan area were impassable due to the heavy rainfall.
Flash Flood · Apr 4, 2025. A stationary front over southern Missouri along with ample mid-level forcing, moisture, and efficient rain processes resulted in flooding across portions of east-central and southeast Missouri. Numerous roads across the St. Louis metropolitan area were impassable due to the heavy rainfall.
Flood · Apr 4, 2025. A stationary front over southern Missouri along with ample mid-level forcing, moisture, and efficient rain processes resulted in flooding across portions of east-central and southeast Missouri. Numerous roads across the St. Louis metropolitan area were impassable due to the heavy rainfall.
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 St. Louis 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.