Photo: Dennisyerger84 · CC BY-SA 3.0More hazard damage per building is expected in Thornton Township than in 87% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Thornton Township gets a D for hazard risk: higher expected damage per building than 87% of U.S. towns, #723 of 768 in Illinois. Most of that expected damage is river and rain flooding (91%). Flood insurance has paid 2,023 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 Thornton Township’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Thornton Township 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
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 Thornton Township’s grade
River and rain flooding is 91% of the building damage FEMA expects in Thornton Township, and Thornton Township’s rate of river and rain flooding damage is in the top 6% of U.S. census tracts. Next is tornadoes at 6% (higher than 83% of U.S. census tracts).
D #723 of 768 in Illinois; higher expected damage per building than 87% of U.S. towns (21,298).
Thornton Township’s residents live in 41 census tracts; FEMA’s figures are combined by where they live.
The typical Illinois town has higher expected damage than 54% of U.S. towns; within the state, Thornton Township has more expected damage per building than 94% of Illinois towns.
Among the 400 U.S. cities of 100,000 or more, Thornton Township has higher expected damage per building than 81% (#324 of 400). Because it is so big, its total expected yearly loss, $104M, is the 111th largest of those 400.
Does Thornton Township flood? Yes: 2,023 flood claims since 1978
Every paid claim on a federal flood insurance policy in Thornton Township, from FEMA’s records: 29.9 per 1,000 homes, more than 88% of the 13,809 U.S. towns with a flood insurance record.
- Hurricane Ike434 claims · $2.6M
- The Mid-spring storms99 claims · $687K
- The Midwest Flooding3 claims · $40K
Thornton Township isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Cook County.The storms Thornton Township remembers
None of the 21 disasters declared for Cook County shows FEMA aid or repair money reaching Thornton Township itself in FEMA’s records, so these are its biggest flood-claim years.
- 2008478 flood claims paidThe year of Severe Storms and Flooding, declared for Cook County
- 1982231 flood claims paidNo declaration for the county that year
- 1981227 flood claims paidThe year of Severe Storms, Flooding and Tornadoes, declared for Cook County
Cook County has had 21 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 Thornton Township after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Thornton Township archive →Thornton Township and its neighbors
Thornton Township is 9th of the 11 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 |
|---|---|---|---|
| Thornton | B+less damage than 65% | river and rain flooding | 4 |
| Hammond | Bless damage than 64% | river and rain flooding | 310 |
| Chicago | B−more damage than 51% | river and rain flooding | 550 |
| North Township | B−more damage than 53% | river and rain flooding | 1,317 |
| Bloom Township | Cmore damage than 66% | river and rain flooding | 238 |
| Lansing | Cmore damage than 74% | river and rain flooding | 209 |
| Bremen Township | Cmore damage than 75% | river and rain flooding | 314 |
| Burnham | C−more damage than 78% | river and rain flooding | 6 |
| Thornton Township | Dmore damage than 87% | river and rain flooding | 2,023 |
| Riverdale | Dmore damage than 88% | river and rain flooding | 4 |
| Calumet Township | Dmore damage than 92% | river and rain flooding | 5 |
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 Thornton Township 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.
- 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 Thornton Township
Is Thornton Township at risk for natural disasters?
On FEMA’s National Risk Index, Thornton Township has higher expected damage per building than 87% of U.S. towns: D for hazard risk, #723 of 768 in Illinois. Most of the expected damage is river and rain flooding (91%) and tornadoes (6%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Thornton Township flood?
Flood insurance has paid 2,023 claims in Thornton Township since 1978, $9.3M in all, or 29.9 per 1,000 homes, more than 88% of U.S. towns with a flood insurance record. The most claims came from Hurricane Ike (434).
Is Thornton Township 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 Cook County, 32% of homes in mapped flood zones carry federal flood insurance, and 0.5% of all homes do.
How much is flood insurance in Thornton Township?
FEMA’s Community Rating System list shows no discount for Thornton Township’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 Thornton Township?
By flood claims, Hurricane Ike: 434 paid, $2.6M.
Is Thornton Township at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (91%), and Thornton Township’s rate for it is in the top 6% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Thornton Township.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Thornton Township’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.