Natural hazards · Grenville

Grenville, SD natural hazards

Most of the natural-hazard damage FEMA expects in Grenville comes from inland flooding, and overall the risk is moderate for a U.S. community.

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

Expected damage

How exposed is Grenville?

Moderate

vs. U.S. communities

FEMA expects yearly storm and flood damage to homes and buildings in Grenville to be higher than in 41% of U.S. communities, mostly from inland flooding and cold waves.

Inland flooding34%Cold waves27%Strong wind14%Tornadoes9%Wildfire5%Everything else11%

By hazard

What Grenville faces

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

Inland flooding

34% of expected damage

Below average · higher than 39% of U.S. places

Recorded about once a year in the area

Cold waves

27% of expected damage

Above average · higher than 66% of U.S. places

Recorded about 14 times a year in the area

Strong wind

14% of expected damage

Well above average · higher than 92% of U.S. places

Recorded about 3 times a year in the area

Tornadoes

9% of expected damage

Well above average · higher than 87% of U.S. places

Recorded about once every 4 years in the area

Wildfire

5% of expected damage

Well above average · higher than 95% of U.S. places

Lower here

HailIce stormsWinter weatherHeat wavesEarthquakesLandslidesLightningDrought

Not a risk here

Coastal floodingHurricanesAvalanchesTsunamisVolcanic 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 Grenville flood?

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

of all homes
are insured

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

Insurance rates: Day County.

Disasters that hit Grenville

Federal disasters declared here

None of the disasters declared for Day County shows FEMA aid or repair money reaching Grenville itself in FEMA’s records.

Brought FEMA money into GrenvilleDeclared for Day County only

Day County has had 23 natural disasters declared since 1953, most often severe storms and floods.

Around Grenville

Grenville and the towns around it

Very lowLowModerateHighVery high

Grenvillemostly inland floodingModerate

Nutleymostly inland floodingModerate

Racinemostly inland floodingModerate

Kosciuskomostly inland floodingModerate

Roslynmostly cold wavesVery low

Raritanmostly cold wavesVery low

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. Grenville 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 Grenville’s own flood-insurance community; household aid to the registrant’s city; repair grants to the Township of Grenville. 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.