Photo: Aykleinman · Public domainFor tornadoes, Duncan’s building-damage rate is in the top 3% of U.S. census tracts
On FEMA’s National Risk Index, Duncan gets a C+ for hazard risk: higher expected damage per building than 55% of U.S. towns, #15 of 131 in Oklahoma. Most of that expected damage is river and rain flooding (47%), then tornadoes (18%). Flood insurance has paid 53 claims here since 1978.
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 stands out about Duncan’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Duncan 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
Hail
Ice storms
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 Duncan’s grade
River and rain flooding is 47% of the building damage FEMA expects in Duncan, and Duncan’s rate of river and rain flooding damage is lower than 66% of U.S. census tracts. Tornadoes add 18%, at a rate in the top 3% of U.S. census tracts.
C+ #15 of 131 in Oklahoma; higher expected damage per building than 55% of U.S. towns (21,298).
Duncan’s residents live in 10 census tracts; FEMA’s figures are combined by where they live.
The typical Oklahoma town has higher expected damage than 69% of U.S. towns; within the state, Duncan has less expected damage per building than 89% of Oklahoma towns.
In dollars, FEMA expects about $11.2M a year in losses across Duncan: $5.9M to buildings, the rest to people and crops.
Does Duncan flood? Sometimes: 53 flood claims since 1978
Every paid claim on a federal flood insurance policy in Duncan, from FEMA’s records: 4.8 per 1,000 homes, more than 59% of the 13,809 U.S. towns with a flood insurance record.
- The Early summer storms3 claims · $7K
Duncan isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Stephens County.17 federal disasters brought FEMA money to Duncan
Disasters that paid out in Duncan itself (aid to households or repair grants to the City of Duncan), newest first, with that year’s flood claims.
- 2024Severe Storms, Straight-line Winds, Tornadoes, and Flooding$98K to the City of Duncan for repairs
- 2023Severe Storms, Straight-line Winds, and Tornadoes$49K to the City of Duncan for repairs
- 2021Severe Winter Storms100 households applied for aid$75K aid approved$493K to the City of Duncan for repairs
- 2020Severe Winter Storm$102K to the City of Duncan for repairs
- 2019Severe Storms, Tornadoes, Straight-line Winds, and Flooding$201K to the City of Duncan for repairs1 flood claim paid that year
- 2016Severe Storms and Flooding$303K to the City of Duncan for repairs2 flood claims paid that year
Show all 17
- 2015Severe Storms, Tornadoes, Straight-line Winds, and Flooding36 households applied for aid$41K aid approved$90K to the City of Duncan for repairs3 flood claims paid that year
- 2011Severe Winter Storm and Snowstorm$16K to the City of Duncan for repairs
- 2010Severe Winter Storm$621K to the City of Duncan for repairs
- 2009Severe Winter Storm$12K to the City of Duncan for repairs
- 2009Wildfires2 households applied for aid$30K aid approved
- 2007Severe Storms, Tornadoes, and Flooding34 households applied for aid$24K aid approved
- 2007Severe Storms, Flooding, and Tornadoes134 households applied for aid$188K aid approved$111K to the City of Duncan for repairs
- 2007Severe Storms, Flooding, and Tornadoes$101K to the City of Duncan for repairs
- 2007Severe Winter Storms$29K to the City of Duncan for repairs
- 2005Extreme Wildfire Threat82 households applied for aid$326K aid approved$32K to the City of Duncan for repairs
- 2000Severe Winter Ice Storm$121K to the City of Duncan for repairs1 flood claim paid that year
Stephens County has had 25 natural disasters declared by the President since 1953, most often severe storms, then winter storms. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Also 2 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Stephens County, 2009–2025.
Old photos of Duncan after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Duncan archive →Duncan and its neighbors
Duncan has the lowest expected damage per building of the 2 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Duncan | C+more damage than 55% | river and rain flooding | 53 |
| Marlow | C+more damage than 63% | river and rain flooding | 4 |
| Empire City | — | 794 residents; we grade 1,000+ | |
| Bray | — | 979 residents; we grade 1,000+ | |
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 Duncan 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.
- 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.
- Ice brings down trees and lines: plan for days without power.
- Run a generator outside, far from doors and windows.
- Keep sand or salt by the door.
- 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 Duncan
Is Duncan at risk for natural disasters?
On FEMA’s National Risk Index, Duncan has higher expected damage per building than 55% of U.S. towns: C+ for hazard risk, #15 of 131 in Oklahoma. Most of the expected damage is river and rain flooding (47%) and tornadoes (18%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Duncan flood?
Flood insurance has paid 53 claims in Duncan since 1978, $552K in all, or 4.8 per 1,000 homes, more than 59% of U.S. towns with a flood insurance record. 5 properties have flooded more than once. The most claims came from Early summer storms (3).
Is Duncan 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 Stephens County, 6% of homes in mapped flood zones carry federal flood insurance, and 0.2% of all homes do.
How much is flood insurance in Duncan?
FEMA’s Community Rating System list shows no discount for Duncan’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 Duncan?
By FEMA money that reached Duncan, Severe Winter Storm (2010): $621K to the City of Duncan for repairs. By flood claims, Early summer storms: 3 paid, $7K.
Is Duncan at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (47%), and Duncan’s rate for it is lower than 66% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Duncan.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Duncan’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.