On FEMA’s figures, Clarkson Valley 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, Clarkson Valley gets a C+ for hazard risk: higher expected damage per building than 56% of U.S. towns, #108 of 247 in Missouri. Most of that expected damage is river and rain flooding (67%), then earthquakes (16%). Flood insurance has paid 1 claim here since 1993.
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 Clarkson Valley 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
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 Clarkson Valley’s grade
River and rain flooding is 67% of the building damage FEMA expects in Clarkson Valley, and Clarkson Valley’s rate of river and rain flooding damage is higher than 59% of U.S. census tracts. Hail adds 12%, at a rate in the top 6% of U.S. census tracts.
C+ #108 of 247 in Missouri; higher expected damage per building than 56% of U.S. towns (21,298).
Clarkson Valley’s residents live in 3 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, Clarkson Valley has less expected damage per building than 57% of Missouri towns.
In dollars, FEMA expects about $2.6M a year in losses across Clarkson Valley: $1.7M to buildings, the rest to people and crops.
Does Clarkson Valley flood? Rarely: 1 flood claim since 1993
Every paid claim on a federal flood insurance policy in Clarkson Valley, from FEMA’s records: 1.1 per 1,000 homes, fewer than 75% of the 13,809 U.S. towns with a flood insurance record.
- The Midwest Flooding1 claim · $11K
Clarkson Valley 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. Louis County.The storms Clarkson Valley remembers
None of the 30 disasters declared for St. Louis County shows FEMA aid or repair money reaching Clarkson Valley itself in FEMA’s records, so these are its biggest flood-claim years.
- 19931 flood claims paidThe year of Severe Storms, Tornadoes, and Flooding, declared for St. Louis County
St. Louis County has had 30 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 Clarkson Valley after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Clarkson Valley archive →Clarkson Valley and its neighbors
Clarkson Valley is 4th of the 5 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Chesterfield | B−less damage than 53% | river and rain flooding | 48 |
| Ellisville | B−less damage than 51% | river and rain flooding | 1 |
| Wildwood | B−more damage than 52% | river and rain flooding | 17 |
| Clarkson Valley | C+more damage than 56% | river and rain flooding | 1 |
| Ballwin | C+more damage than 62% | river and rain flooding | 38 |
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 Clarkson Valley 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.
- 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 Clarkson Valley
Is Clarkson Valley at risk for natural disasters?
On FEMA’s National Risk Index, Clarkson Valley has higher expected damage per building than 56% of U.S. towns: C+ for hazard risk, #108 of 247 in Missouri. Most of the expected damage is river and rain flooding (67%) and earthquakes (16%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Clarkson Valley flood?
Flood insurance has paid 1 claim in Clarkson Valley since 1993, $11K in all, or 1.1 per 1,000 homes, fewer than 75% of U.S. towns with a flood insurance record. The most claims came from Midwest Flooding (1).
Is Clarkson Valley 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. Louis County, 34% of homes in mapped flood zones carry federal flood insurance, and 0.6% of all homes do.
How much is flood insurance in Clarkson Valley?
FEMA’s Community Rating System list shows no discount for Clarkson Valley’s 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 Clarkson Valley?
By flood claims, Midwest Flooding: 1 paid, $11K.
Is Clarkson Valley at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (67%), and Clarkson Valley’s rate for it is higher than 59% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Clarkson Valley.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Clarkson Valley’s 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.