Natural hazards · Union

Union, SD natural hazards

Most of the natural-hazard damage FEMA expects in Union comes from cold waves, and overall the risk is very low for a U.S. community.

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

Expected damage

How exposed is Union?

Very low

vs. U.S. communities

FEMA expects yearly storm and flood damage to homes and buildings in Union to be higher than in 18% of U.S. communities, mostly from cold waves and inland flooding.

Cold waves33%Inland flooding23%Strong wind15%Tornadoes10%Hail10%Everything else10%

By hazard

What Union faces

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

Cold waves

33% of expected damage

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

Recorded about 14 times a year in the area

Inland flooding

23% of expected damage

Well below average · higher than 12% of U.S. places

Recorded about once a year in the area

Strong wind

15% of expected damage

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

Recorded about 3 times a year in the area

Tornadoes

10% of expected damage

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

Recorded about once every 3 years in the area

Hail

10% of expected damage

Above average · higher than 72% of U.S. places

Recorded about 4 times a year in the area

Lower here

Ice stormsWinter weatherHeat wavesWildfireEarthquakesLandslidesLightning

Not a risk here

Coastal floodingHurricanesDroughtAvalanchesTsunamisVolcanic 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 Union flood?

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

of all homes
are insured

No community discount. Union 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 Union

Federal disasters declared here

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

Brought FEMA money into UnionDeclared for Day County only

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

Around Union

Union and the towns around it

Very lowLowModerateHighVery high

Unionmostly cold wavesVery low

Andovermostly cold wavesVery low

Lynnmostly cold wavesVery low

Bristolmostly cold wavesVery low

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