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Rock County, Wisconsin

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

Relatively Moderate overall risk
7th of 72highest risk in Wisconsin
$73Mexpected losses a year
14federal declarations
1 in 250homes with flood insurance
Photo: U.S. Geological Survey, public domain

Rock County, Wisconsin has a moderate overall risk from natural hazards in FEMA's National Risk Index. Its risk score is higher than 86% of US counties. It ranks 7th of 72 counties in Wisconsin. The costliest hazards here are inland flooding, tornadoes and cold waves. FEMA estimates about $73 million a year in expected losses, or roughly $448 per resident. Since 1973 it has been included in 14 federal disaster or emergency declarations for natural events (10 major disasters). The most recent was in June 2026 (severe storms, tornadoes and flooding). Fewer than 1 in 100 homes here carry federal flood insurance (221 policies). Since 1978, federal flood insurance has paid about $4.4 million on 305 claims here, including $3.6 million for floods in 2008.

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

Top risks in Rock County

$37.9 million a yearExpected losses. Damaging events about 2 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.
$12.9 million a yearExpected losses. Damaging events about once every 2 years.
  • 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.
$12.6 million a yearExpected losses. Damaging events about 5 times a year.
  • Insulate pipes in outside walls, crawl spaces and garages.
  • Know how to shut off the main water valve.
HazardRatingScoreExpected loss a year
Inland floodingModerate87.6
$38M
TornadoHigh94.3
$13M
Cold waveHigh94.1
$13M
HailHigh95.6
$4M
Strong windHigh86.2
$2M
Heat waveModerate80.8
$2M
LightningHigh84.7
$1M
EarthquakeVery Low59.3
$529K
DroughtLow48.0
$152K
Ice stormLow57.9
$147K
Winter weatherModerate61.2
$114K
WildfireVery Low26.8
$14K
HurricaneVery Low14.9
$4K
LandslideVery Low60.1
$3K

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 very low and community resilience is very high in FEMA's measures.

Federal disaster history

Recent disasters nationwide ›

Declarations by decade

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

By type

Severe Storm7
Flood3
Snowstorm2
Drought1
Hurricane1

Most recent

Jun 30, 2026Severe Storms, Tornadoes, and FloodingMajor disaster
Jun 14, 2008Severe Storms, Tornadoes, and FloodingMajor disaster
Mar 19, 2008Record Snow and Near Record SnowEmergency
Aug 26, 2007Severe Storms and FloodingMajor disaster
Sep 13, 2005Hurricane Katrina EvacuationEmergency
Jun 18, 2004Severe Storms and FloodingMajor disaster
Jan 24, 2001SnowEmergency
Aug 12, 1998Severe Storms and FloodingMajor disaster
Jul 2, 1993Severe Storms, Tornadoes & FloodingMajor disaster
Jul 13, 1990Severe Storms, Tornadoes & FloodingMajor disaster
Show all 14
Jul 7, 1978Severe Storms, Flooding, Hail & TornadoesMajor disaster
Jun 17, 1976DroughtEmergency
Mar 23, 1976Severe Storms, Icing, Wind & FloodingMajor disaster
Apr 27, 1973Severe Storms & FloodingMajor disaster

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

Storm history since 1955

Tornado risk by county ›

The National Weather Service has logged 731 storm reports in Rock County since 1955, with 1 death and 21 injuries and about $107 million in reported damage. The strongest on record here was an EF2 tornado on June 22, 2024 near Afton.

38tornadoes
174hail reports, largest 3 inches
383damaging thunderstorm winds
83floods and flash floods

Strongest tornadoes

DateStrengthNearHurt / killed
Jun 22, 2024EF2Afton0 / 0
Feb 8, 2024EF2Magnolia1 / 0
Mar 27, 1991F2–0 / 0
Jun 25, 1998F2Leyden0 / 0
Oct 9, 1970F2–1 / 0

Most damaging storms

DateTypeNearDamage
Apr 17, 2026Flash FloodDowntown Janesville$30M
Jun 22, 2024TornadoAfton$25M
Feb 8, 2024TornadoMagnolia$7M
Aug 5, 2000Thunderstorm WindEvansville$6M
Apr 13, 2006HailUnion$4M
Jun 1, 2000Flash FloodCountywide$4M

Source: NOAA Storm Events Database, county-based reports through Jul 3, 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 Rock County

Check your address flood zone ›
0.4%of homes have federal flood insurance (221 policies)
32.7%of homes in mapped high-risk flood zones are insured
$4.4 millionpaid on 305 flood claims since 1978
2008costliest year, with $3.6 million 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 Rock County

$231,600median home value (Wisconsin $266,500, US $332,700)
1970median year homes were built (Wisconsin 1975, US 1980)
65%of homes built before 1980, before many modern wind, quake and flood building rules
2.6%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; 71,109 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
Dane CountyModerate17
Winnebago County, ILModerate17
Walworth CountyLow11
Jefferson CountyLow12
Boone County, ILLow9
Green CountyLow15

Cities in Rock County

Common questions about Rock County

What is the biggest natural hazard in Rock County?

Inland flooding has the highest expected yearly losses in Rock County, about $37.9 million a year in FEMA's estimate. Tornado is second at $12.9 million.

How many federal disasters has Rock County had?

Rock County has been included in 14 federal disaster or emergency declarations for natural events since 1973, including 10 major disasters. The most recent was Severe Storms, Tornadoes, and Flooding in June 2026.

Is Rock County a high-risk place to live?

Its overall rating is Relatively Moderate, 7th 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 Rock County?

Standard home insurance does not cover flooding. About 1 in 250 homes in Rock 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 Rock County had?

NOAA records list 38 tornadoes in Rock County since 1950. The strongest was an EF2 tornado on June 22, 2024 near Afton. The weather service has also logged 174 hail reports and 83 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.