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Grant County, Wisconsin

Natural disaster risk, federal disaster history and flood insurance facts.

Relatively Low overall risk
41st of 72highest risk in Wisconsin
$21Mexpected losses a year
18federal declarations
1 in 250homes with flood insurance
Photo: U.S. Geological Survey, public domain

Grant County, Wisconsin has a relatively low overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 61% of US counties. It ranks 41st of 72 counties in Wisconsin. The costliest hazards here are inland flooding, cold waves and tornadoes. FEMA estimates about $21 million a year in expected losses, or roughly $407 per resident. Since 1965 it has been included in 18 federal disaster or emergency declarations for natural events (16 major disasters). The most recent was in October 2017 (severe storms, straight-line winds, flooding, landslides and mud). Fewer than 1 in 100 homes here carry federal flood insurance (64 policies). Since 1978, federal flood insurance has paid about $624,000 on 85 claims here.

FEMA National Risk Index December 2025; OpenFEMA declarations to Nov 6, 2026; NFIP records. Updated November 6, 2026.

Top risks in Grant County

$9.2 million a yearExpected losses. Damaging events about 3 times a year.
  • Check the FEMA flood map for your address, and ask the seller or landlord about past flooding.
  • Price a flood policy now. Most new federal policies take 30 days to start.

Cold wave

Moderate
$3.7 million a yearExpected losses. Damaging events about 6 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.

Tornado

Moderate
$3.1 million a yearExpected losses. Damaging events about once a year.
  • Pick a shelter spot: a basement, or an inside room on the lowest floor with no windows.
  • Turn on emergency alerts on your phone and keep a weather radio.
HazardRatingScoreExpected loss a year
Inland floodingLow62.2
$9M
Cold waveModerate80.9
$4M
TornadoModerate76.4
$3M
HailModerate89.7
$2M
Strong windModerate82.7
$1M
Heat waveLow63.0
$628K
LightningModerate75.0
$567K
DroughtModerate64.7
$366K
LandslideModerate95.5
$140K
Ice stormLow53.4
$93K
EarthquakeVery Low29.8
$70K
Winter weatherLow50.5
$61K
WildfireVery Low16.7
$6K
HurricaneVery Low15.3
$4K

Scores are percentiles: a score of 90 means higher risk than about 90% of US counties for that hazard. Hazards FEMA does not rate here are left out. Social vulnerability is relatively moderate and community resilience is relatively high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

Federal declarations for natural events that included Grant County. 2020s bar runs to November 2026.

By type

Severe Storm10
Flood4
Tornado1
Drought1
Hurricane1
Snowstorm1

Most recent

Oct 7, 2017Severe Storms, Straight-Line Winds, Flooding, Landslides, and MudMajor disaster
Aug 8, 2013Severe Storms, Flooding, and MudslidesMajor disaster
Apr 5, 2011Severe Winter Storm and SnowstormMajor disaster
Aug 11, 2010Severe Storms, Tornadoes, and FloodingMajor disaster
Jun 14, 2008Severe Storms, Tornadoes, and FloodingMajor disaster
Aug 26, 2007Severe Storms and FloodingMajor disaster
Sep 13, 2005Hurricane Katrina EvacuationEmergency
Jun 18, 2004Severe Storms and FloodingMajor disaster
May 11, 2001Flooding, Severe Storms and TornadoesMajor disaster
Jun 24, 2000Severe Storms, Tornadoes, and FloodingMajor disaster
Show all 18
Jul 24, 1998Severe Storms,Straigh Line Winds, Tornadoes,Rain,And FloodiMajor disaster
Jul 2, 1993Severe Storms, Tornadoes & FloodingMajor disaster
Jul 13, 1990Severe Storms, Tornadoes & FloodingMajor disaster
Jun 17, 1976DroughtEmergency
Mar 23, 1976Severe Storms, Icing, Wind & FloodingMajor disaster
Jul 11, 1969Severe Storms & FloodingMajor disaster
May 1, 1969FloodingMajor disaster
Apr 21, 1965Tornadoes, Severe Storms & FloodingMajor disaster

Wisconsin also had 8 statewide declarations that did not name single counties.

Storm history since 1954

Tornado risk by county ›

The National Weather Service has logged 829 storm reports in Grant County since 1954, with 2 deaths and 13 injuries and about $98.8 million in reported damage. The strongest on record here was an F3 tornado on May 30, 1985.

56tornadoes
255hail reports, largest 3 inches
347damaging thunderstorm winds
134floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
May 30, 1985F3–2 / 0
Aug 7, 2021EF3Boscobel0 / 0
Jun 16, 2014EF2Platteville5 / 0
Sep 4, 2012EF2Patch Grove0 / 0
Jul 13, 1966F2–0 / 0

Most damaging storms

DateTypeNearDamage
Jun 16, 2014TornadoPlatteville$21M
Jul 24, 2009HailPotosi$10M
Jul 21, 2017Flash FloodGlenhaven$9M
Jul 24, 2009HailLancaster$8M
Jun 22, 2013Flash FloodBoscobel$7M
Jun 12, 2008Flash FloodCassville$7M

Source: NOAA Storm Events Database, county-based reports through Jul 2, 2026. Tornado records start in 1950, hail and wind in 1955, and floods and other storm types in 1996, so older decades undercount. Damage is in dollars of the year it happened and is often an estimate. Winter storms, heat and hurricanes are logged by forecast zone, not county, so they are not counted here.

Flood insurance in Grant County

Check your address flood zone ›
0.4%of homes have federal flood insurance (64 policies)
15.2%of homes in mapped high-risk flood zones are insured
$624,067paid on 85 flood claims since 1978
2017costliest year, with $138,118 paid

National Flood Insurance Program (NFIP) records only; private flood policies are not included. Home counts as of Aug 3, 2026. Since 2021 NFIP prices each home separately under Risk Rating 2.0, so your price depends on the building, not the county. Ask an agent for a quote.

Homes in Grant County

$200,700median home value (Wisconsin $266,500, US $332,700)
1973median year homes were built (Wisconsin 1975, US 1980)
61%of homes built before 1980, before many modern wind, quake and flood building rules
4.9%of homes are mobile homes, which are the least safe in tornadoes and high winds

Older homes and mobile homes usually suffer more damage in storms, floods and earthquakes, and can cost more to insure. If you are buying, ask about roof age, foundation bolting and any retrofits. Source: US Census Bureau, American Community Survey 2020 to 2024 5-year estimates; 22,332 housing units.

Compare in Wisconsin

All 72 ›
Largest countiesOverall riskTop hazard
Milwaukee CountyHighCold wave
Dane CountyModerateInland flooding
Waukesha CountyModerateInland flooding
Brown CountyModerateInland flooding
Racine CountyModerateInland flooding
Outagamie CountyLowInland flooding
Winnebago CountyModerateInland flooding
Kenosha CountyModerateCold wave

Neighboring counties

CountyOverall riskDeclarations
Dubuque County, IALow19
Iowa CountyVery Low15
Jo Daviess County, ILLow14
Richland CountyLow17
Clayton County, IAVery Low25
Lafayette CountyVery Low12
Crawford CountyLow20

Common questions about Grant County

What is the biggest natural hazard in Grant County?

Inland flooding has the highest expected yearly losses in Grant County, about $9.2 million a year in FEMA's estimate. Cold wave is second at $3.7 million.

How many federal disasters has Grant County had?

Grant County has been included in 18 federal disaster or emergency declarations for natural events since 1965, including 16 major disasters. The most recent was Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mud in October 2017.

Is Grant County a high-risk place to live?

Its overall rating is Relatively Low, 41st highest of 72 in Wisconsin. A county rating covers the whole area. Risk at one address can be much higher or lower, so check the FEMA flood map and ask about the home's history.

Do I need flood insurance in Grant County?

Standard home insurance does not cover flooding. About 1 in 250 homes in Grant County has federal flood insurance. Lenders require it in mapped high-risk zones, but many flood claims come from outside those zones.

How many tornadoes has Grant County had?

NOAA records list 56 tornadoes in Grant County since 1950. The strongest was an F3 tornado on May 30, 1985. The weather service has also logged 255 hail reports and 134 floods here.

Sources: FEMA National Risk Index (December 2025), OpenFEMA Disaster Declarations Summaries, and NFIP policy and claims data. Hazard Compass is independent and not affiliated with FEMA. These figures describe the whole county, not a single property, and are not insurance or safety advice. Report a problem.