Natural hazards · Ontario

Ontario, IL natural hazards

Most of the natural-hazard damage FEMA expects in Ontario comes from inland flooding, and overall the risk is moderate for a U.S. community. 2 federal disasters brought FEMA money into town.

FEMA National Risk Index, December 2025 · OpenFEMA claims, aid & declarations

Expected damage

How exposed is Ontario?

Moderate

vs. U.S. communities

FEMA expects yearly storm and flood damage to homes and buildings in Ontario to be higher than in 59% of U.S. communities, mostly from inland flooding and strong winds.

Inland flooding27%Strong wind17%Drought15%Cold waves13%Tornadoes11%Hail6%Everything else11%

By hazard

What Ontario faces

Each hazard’s share of the damage FEMA expects here, and how that compares with the rest of the country.

Inland flooding

27% of expected damage

Above average · higher than 63% of U.S. places

Recorded about once a year in the area

Strong wind

17% of expected damage

Well above average · higher than 98% of U.S. places

Recorded about 6 times a year in the area

Drought

15% of expected damage

Recorded about 9 times a year in the area

Cold waves

13% of expected damage

Above average · higher than 62% of U.S. places

Recorded about 6 times a year in the area

Tornadoes

11% of expected damage

Well above average · higher than 90% of U.S. places

Recorded about once every 5 years in the area

Hail

6% of expected damage

Well above average · higher than 94% of U.S. places

Recorded about 4 times a year in the area

Lower here

HurricanesIce stormsWinter weatherWildfireEarthquakesLandslidesLightning

Not a risk here

Coastal floodingAvalanchesTsunamisVolcanic activity

Flood risk changes street by street. Check a specific address on FEMA’s flood map, and ask about flood insurance before you buy.

Flood insurance claims

Does Ontario flood?

FEMA's records show no paid flood insurance claims in Ontario.

of homes in flood zones
are insured

of all homes
are insured

No community discount. Ontario isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.

Insurance rates: Knox County.

Disasters that hit Ontario

2 federal disasters brought FEMA money here

Disasters the President declared that paid out in Ontario itself: aid to households, or repair grants to the Township of Ontario.

Brought FEMA money into OntarioDeclared for Knox County only

2011

Severe Winter Storm and Snowstorm

$6K to the Township of Ontario for repairs

1999

Il-Winter Storm 1/1/99

$2K to the Township of Ontario for repairs

Knox County has had 9 natural disasters declared since 1953, most often floods and winter storms.

Around Ontario

Ontario and the towns around it

Very lowLowModerateHighVery high

Spartamostly inland floodingHigh

Ontariomostly inland floodingModerate

Walnut Grovemostly inland floodingModerate

Riomostly inland floodingModerate

Clovermostly inland floodingModerate

About these numbers

How to read this page

An average, not a forecastFEMA’s National Risk Index estimates the damage 18 kinds of natural hazards cause in a typical year, from decades of records and models. A quiet decade can follow a bad year.

Compared by rate“Higher than N%” compares yearly damage as a share of what’s here, so a big city isn’t rated riskier just for having more buildings. Ontario is smaller than a census tract, so it shares the figures of the tract around its center.

Money that reached townFlood claims are matched to Ontario’s own flood-insurance community; household aid to the registrant’s city; repair grants to the Township of Ontario. FEMA’s model follows property values, so a place that recently lost many homes can rate lower than it feels.

Sources: FEMA National Risk Index (December 2025); 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. Census tracts: U.S. Census Bureau.