Photo: Roastedbeanz1 · CC BY-SA 4.0On FEMA’s figures, Lake St. Louis faces about as much hazard damage per building as the typical U.S. town, mostly from river and rain flooding
On FEMA’s National Risk Index, Lake St. Louis gets a C+ for hazard risk: higher expected damage per building than 58% of U.S. towns, #117 of 247 in Missouri. Most of that expected damage is river and rain flooding (72%). Flood insurance has paid 5 claims here since 1982.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What Lake St. Louis faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Tornadoes
Earthquakes
Hail
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind Lake St. Louis’ grade
River and rain flooding is 72% of the building damage FEMA expects in Lake St. Louis, and Lake St. Louis’ rate of river and rain flooding damage is higher than 64% of U.S. census tracts. Next is tornadoes at 10% (higher than 80% of U.S. census tracts).
C+ #117 of 247 in Missouri; higher expected damage per building than 58% of U.S. towns (21,298).
Lake St. Louis’ residents live in 7 census tracts; FEMA’s figures are combined by where they live.
The typical Missouri town has higher expected damage than 59% of U.S. towns; within the state, Lake St. Louis has less expected damage per building than 53% of Missouri towns.
In dollars, FEMA expects about $7.7M a year in losses across Lake St. Louis: $5.3M to buildings, the rest to people and crops.
Does Lake St. Louis flood? Rarely: 5 flood claims since 1982
Every paid claim on a federal flood insurance policy in Lake St. Louis, from FEMA’s records: 0.7 per 1,000 homes, fewer than 86% of the 13,809 U.S. towns with a flood insurance record.
- The Early winter storms1 claim · $4K
Lake St. Louis isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: St. Charles County.4 federal disasters brought FEMA money to Lake St. Louis
Disasters that paid out in Lake St. Louis itself (aid to households or repair grants to the City of Lake St. Louis), newest first, with that year’s flood claims.
- 2022Severe Storms and Flooding73 households applied for aid$94K aid approved
- 2015Severe Storms, Tornadoes, Straight-line Winds, and Flooding2 households applied for aid$2K aid approved1 flood claim paid that year
- 2008Severe Storms, Flooding, and a Tornado2 households applied for aid$3K aid approved
- 2007Severe Winter Storms and Flooding$35K to the City of Lake St. Louis for repairs
St. Charles County has had 24 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Lake St. Louis after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Lake St. Louis archive →Lake St. Louis and its neighbors
Lake St. Louis has the lowest expected damage per building of the 4 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Lake St. Louis | C+more damage than 58% | river and rain flooding | 5 |
| Wentzville | C+more damage than 62% | river and rain flooding | 4 |
| O'Fallon | C−more damage than 81% | river and rain flooding | 45 |
| Dardenne Prairie | Dmore damage than 88% | river and rain flooding | 1 |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what Lake St. Louis faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Pick your spot now: the lowest floor, an inside room, no windows.
- A watch means be ready; a warning means take cover now.
- Keep shoes and a flashlight by the bed.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- Park in a garage or under cover when storms are forecast.
- Stay away from windows while it falls.
- Photograph roof and car damage for your insurer.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in Lake St. Louis
Is Lake St. Louis at risk for natural disasters?
On FEMA’s National Risk Index, Lake St. Louis has higher expected damage per building than 58% of U.S. towns: C+ for hazard risk, #117 of 247 in Missouri. Most of the expected damage is river and rain flooding (72%) and tornadoes (10%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Lake St. Louis flood?
Flood insurance has paid 5 claims in Lake St. Louis since 1982, $24K in all, or 0.7 per 1,000 homes, fewer than 86% of U.S. towns with a flood insurance record. The most claims came from Early winter storms (1).
Is Lake St. Louis in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In St. Charles County, 35% of homes in mapped flood zones carry federal flood insurance, and 0.8% of all homes do.
How much is flood insurance in Lake St. Louis?
FEMA’s Community Rating System list shows no discount for Lake St. Louis’ flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in Lake St. Louis?
By FEMA money that reached Lake St. Louis, Severe Storms and Flooding (2022): 73 households applied for aid, $94K approved. By flood claims, Early winter storms: 1 paid, $4K.
Is Lake St. Louis at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (72%), and Lake St. Louis’ rate for it is higher than 64% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Lake St. Louis.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Lake St. Louis’ residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.