Photo: Andy McMurray · CC BY 2.5FEMA expects less hazard damage per building in Marengo than in 69% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Marengo gets a B+ for hazard risk: lower expected damage per building than 69% of U.S. towns, #149 of 768 in Illinois. Most of that expected damage is river and rain flooding (82%), then tornadoes (14%). Flood insurance has paid 12 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 Marengo 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 Marengo’s grade
River and rain flooding is 82% of the building damage FEMA expects in Marengo, and Marengo’s rate of river and rain flooding damage is higher than 53% of U.S. census tracts. Next is tornadoes at 14% (higher than 83% of U.S. census tracts).
B+ #149 of 768 in Illinois; lower expected damage per building than 69% of U.S. towns (21,298).
Marengo’s residents live in 2 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, Marengo has less expected damage per building than 81% of Illinois towns.
In dollars, FEMA expects about $3.8M a year in losses across Marengo: $2.6M to buildings, the rest to people and crops.
Does Marengo flood? Sometimes: 12 flood claims since 1978
Every paid claim on a federal flood insurance policy in Marengo, from FEMA’s records: 4.3 per 1,000 homes, more than 56% of the 13,809 U.S. towns with a flood insurance record.
- The Mid-spring storms1 claim · $3K
Marengo isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: McHenry County.4 federal disasters brought FEMA money to Marengo
Disasters that paid out in Marengo itself (aid to households or repair grants to the City of Marengo), newest first, with that year’s flood claims.
- 2013Severe Storms, Straight-line Winds, and Flooding4 households applied for aid$3K aid approved1 flood claim paid that year
- 2011Severe Winter Storm and Snowstorm$13K to the City of Marengo for repairs
- 2006Snow$16K to the City of Marengo for repairs
- 1999Il-winter Storm 1/1/99$8K to the City of Marengo for repairs
McHenry County has had 13 natural disasters declared by the President since 1953, most often winter storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Old photos of Marengo after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Marengo archive →Marengo and its neighbors
Marengo has the lowest expected damage per building of the 1 graded towns here. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Marengo | B+less damage than 69% | river and rain flooding | 12 |
| Riley | — | 0 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 Marengo 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 Marengo
Is Marengo at risk for natural disasters?
On FEMA’s National Risk Index, Marengo has lower expected damage per building than 69% of U.S. towns: B+ for hazard risk, #149 of 768 in Illinois. Most of the expected damage is river and rain flooding (82%) and tornadoes (14%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Marengo flood?
Flood insurance has paid 12 claims in Marengo since 1978, $30K in all, or 4.3 per 1,000 homes, more than 56% of U.S. towns with a flood insurance record. 1 properties have flooded more than once. The most claims came from Mid-spring storms (1).
Is Marengo 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 McHenry County, 19% of homes in mapped flood zones carry federal flood insurance, and 0.7% of all homes do.
How much is flood insurance in Marengo?
FEMA’s Community Rating System list shows no discount for Marengo’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 Marengo?
By FEMA money that reached Marengo, Snow (2006): $16K to the City of Marengo for repairs. By flood claims, Mid-spring storms: 1 paid, $3K.
Is Marengo at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (82%), and Marengo’s rate for it is higher than 53% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Marengo.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Marengo’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.