Rock County, Wisconsin
Natural disaster risk, federal disaster history and flood insurance facts.
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
- 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.
- 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.
- Insulate pipes in outside walls, crawl spaces and garages.
- Know how to shut off the main water valve.
All 18 hazards
What the ratings mean ›| Hazard | Rating | Score | Expected loss a year | |
|---|---|---|---|---|
| Inland flooding | 87.6 | $38M | ||
| Tornado | 94.3 | $13M | ||
| Cold wave | 94.1 | $13M | ||
| Hail | 95.6 | $4M | ||
| Strong wind | 86.2 | $2M | ||
| Heat wave | 80.8 | $2M | ||
| Lightning | 84.7 | $1M | ||
| Earthquake | 59.3 | $529K | ||
| Drought | 48.0 | $152K | ||
| Ice storm | 57.9 | $147K | ||
| Winter weather | 61.2 | $114K | ||
| Wildfire | 26.8 | $14K | ||
| Hurricane | 14.9 | $4K | ||
| Landslide | 60.1 | $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
Most recent
Show all 14
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.
Strongest tornadoes
| Date | Strength | Near | Hurt / killed |
|---|---|---|---|
| Jun 22, 2024 | EF2 | Afton | 0 / 0 |
| Feb 8, 2024 | EF2 | Magnolia | 1 / 0 |
| Mar 27, 1991 | F2 | – | 0 / 0 |
| Jun 25, 1998 | F2 | Leyden | 0 / 0 |
| Oct 9, 1970 | F2 | – | 1 / 0 |
Most damaging storms
| Date | Type | Near | Damage |
|---|---|---|---|
| Apr 17, 2026 | Flash Flood | Downtown Janesville | $30M |
| Jun 22, 2024 | Tornado | Afton | $25M |
| Feb 8, 2024 | Tornado | Magnolia | $7M |
| Aug 5, 2000 | Thunderstorm Wind | Evansville | $6M |
| Apr 13, 2006 | Hail | Union | $4M |
| Jun 1, 2000 | Flash Flood | Countywide | $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 ›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
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 counties | Overall risk | Top hazard |
|---|---|---|
| Milwaukee County | Cold wave | |
| Dane County | Inland flooding | |
| Waukesha County | Inland flooding | |
| Brown County | Inland flooding | |
| Racine County | Inland flooding | |
| Outagamie County | Inland flooding | |
| Winnebago County | Inland flooding | |
| Kenosha County | Cold wave |
Neighboring counties
| County | Overall risk | Declarations |
|---|---|---|
| Dane County | 17 | |
| Winnebago County, IL | 17 | |
| Walworth County | 11 | |
| Jefferson County | 12 | |
| Boone County, IL | 9 | |
| Green County | 15 |
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.