Photo: AlphaBeta135 · CC BY 4.0Less hazard damage per building is expected in Algonquin than in 68% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, Algonquin gets a B+ for hazard risk: lower expected damage per building than 68% of U.S. towns, #156 of 768 in Illinois. Most of that expected damage is river and rain flooding (82%), then tornadoes (14%). Flood insurance has paid 48 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 Algonquin’s natural hazards
From FEMA’s model and FEMA’s records, below.
What Algonquin 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 Algonquin’s grade
River and rain flooding is 82% of the building damage FEMA expects in Algonquin, and Algonquin’s rate of river and rain flooding damage is higher than 54% of U.S. census tracts. Next is tornadoes at 14% (higher than 83% of U.S. census tracts).
B+ #156 of 768 in Illinois; lower expected damage per building than 68% of U.S. towns (21,298).
Algonquin’s residents live in 11 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, Algonquin has less expected damage per building than 80% of Illinois towns.
In dollars, FEMA expects about $12.3M a year in losses across Algonquin: $8.1M to buildings, the rest to people and crops.
Does Algonquin flood? Sometimes: 48 flood claims since 1978
Every paid claim on a federal flood insurance policy in Algonquin, 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 Midwest Flooding4 claims · $53K
- The Mid-spring storms3 claims · $52K
- Tropical Storm Erin1 claim · $5K
Algonquin 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.8 federal disasters brought FEMA money to Algonquin
Disasters that paid out in Algonquin itself (aid to households or repair grants to the Village of Algonquin), newest first, with that year’s flood claims.
- 2013Severe Storms, Straight-line Winds, and Flooding43 households applied for aid$47K aid approved$85K to the Village of Algonquin for repairs3 flood claims paid that year
- 2011Severe Winter Storm and Snowstorm$77K to the Village of Algonquin for repairs
- 2008Severe Storms and Flooding2 households applied for aid$2K aid approved
- 2008Record Snow and Near Record Snow$43K to the Village of Algonquin for repairs
- 2007Severe Storms and Flooding7 households applied for aid$21K aid approved7 flood claims paid that year
- 2006Snow$27K to the Village of Algonquin for repairs
Show all 8
- 2000Illinois Winter Snow Storms$20K to the Village of Algonquin for repairs
- 1999Il-winter Storm 1/1/99$21K to the Village of Algonquin for repairs1 flood claim paid that year
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 Algonquin after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Algonquin archive →Algonquin and its neighbors
Algonquin is 4th of the 8 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 |
|---|---|---|---|
| Carpentersville | Aless damage than 89% | river and rain flooding | 5 |
| Dundee Township | Aless damage than 85% | river and rain flooding | 56 |
| Rutland Township | A−less damage than 78% | river and rain flooding | — |
| Algonquin | B+less damage than 68% | river and rain flooding | 48 |
| Lake in the Hills | Bless damage than 62% | river and rain flooding | 31 |
| Grafton Township | Bless damage than 61% | river and rain flooding | 5 |
| Barrington Hills | B−less damage than 54% | river and rain flooding | 3 |
| Cary | C+more damage than 61% | river and rain flooding | 11 |
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 Algonquin 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 Algonquin
Is Algonquin at risk for natural disasters?
On FEMA’s National Risk Index, Algonquin has lower expected damage per building than 68% of U.S. towns: B+ for hazard risk, #156 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 Algonquin flood?
Flood insurance has paid 48 claims in Algonquin since 1978, $369K in all, or 4.3 per 1,000 homes, more than 56% of U.S. towns with a flood insurance record. 6 properties have flooded more than once. The most claims came from Midwest Flooding (4).
Is Algonquin 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 Algonquin?
FEMA’s Community Rating System list shows no discount for Algonquin’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 Algonquin?
By FEMA money that reached Algonquin, Severe Storms, Straight-line Winds, and Flooding (2013): 43 households applied for aid, $47K approved, and $85K to the Village of Algonquin for repairs. By flood claims, Midwest Flooding: 4 paid, $53K.
Is Algonquin at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (82%), and Algonquin’s rate for it is higher than 54% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Algonquin.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Algonquin’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.