Rock County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Rock County: 0.
2. Weak tornadoes were under-recorded before Doppler radar coverage became national in the early 1990s, so earlier decades read low. Ratings use the Fujita scale before February 2007 and the Enhanced Fujita scale after.

Storm Prediction Center severe weather database, 1950 to 2025.

Smoke overhead

1. A smoke day is a date on which a smoke plume traced by NOAA Hazard Mapping System analysts from satellite imagery covered this place's point (the county's population centre or the city centre). Counts here are of medium or heavy smoke. Since 2018 analysts have often drawn light smoke as one area over most of the continent, so light-smoke counts are not comparable from year to year. The plumes show smoke anywhere in the air above, not air quality at the ground, and smoke hidden by cloud is missed.

NOAA Hazard Mapping System smoke analysis, 2011 to 2026, retrieved October 30, 2026.

Claims by ZIP code

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026. NOAA Storm Events through 2026.

River crests

River gauges

1. Crests are the highest and the recent crests the National Weather Service lists for each river gauge in the county that has a flood stage, not every flood. Flood categories use each gauge's current flood stages; crests from before levees, dams or channel changes may not be comparable. Crests measured on an old datum are left out of the rankings.

NOAA National Water Prediction Service gauge records, retrieved October 30, 2026.

1. The Palmer Drought Severity Index is computed by NOAA each month from the county's average temperature and precipitation, relative to the county's own climate. Zero is normal; -3 or lower is severe drought and -4 or lower extreme drought. It describes the long-term balance of moisture, not water supply or crop losses.

NOAA NCEI nClimDiv county Palmer Drought Severity Index, 1895 to September 2026, issued October 6, 2026.

1. Earthquakes of magnitude 2.5 or more in the USGS Comprehensive Catalog since 1900. Within 50 miles means the epicentre lies within 50 miles of the county boundary (or inside the county).
2. Small earthquakes were under-recorded before the modern seismic networks of the 1970s and are still missed in remote areas, so early decades read low. Magnitudes are as the catalogue reports them and mix scales (moment, local and body-wave).

USGS ANSS Comprehensive Earthquake Catalog, 1900 to present, retrieved October 30, 2026.

More event types since 1996

Costliest events since 1996

1. Apr 17, 2026Flash Flood$30.0 million
   National Weather Service narrative

   Around 700 911 calls mainly attributed to flash flooding. Flash flooding of streets and yards in Janesville with basement flooding in many homes. Many vehicles stranded in deep water. A bridge was washed out due to the flooding of Fisher Creek over Rockport Rd. Severe flooding of a church, and the basement of an elementary school. The school's mechanical systems and main power panel were destroyed. The school has been closed. RAJ stadium flooded. A train derailment in downtown Janesville with 3 locomotives off the tracks, due to a sinkhole. 1st responders conducted a water rescue of the engineer using a rope.

2. Jun 22, 2024Tornado$24.8 million
   National Weather Service narrative

   The tornado began just west of Murray Rd, north of Bass Creek where portions of several trees were snapped. The tornado quickly grew, moved to the east-northeast and produced damage rated EF-1 neighborhoods near Loch Lomond park. EF-2 damage was noted at a residence on the east side of county highway D where well over one hundred trees were snapped or uprooted. The tornado continued to the northeast, crossing the Rock River, Highway 11 and Highway 51 producing damage rated EF-1. The second area of EF-2 damage was noted a neighborhood just northwest of Burbank Park, where a house lost its roof and a portion of its second story. The roof was found to the north-northwest over a block…

3. Feb 8, 2024Tornado$6.8 million
   National Weather Service narrative

   Beginning section of the second tornado to ever occur in February in Wisconsin. Storm chaser/spotter/public videos show the tornado beginning around 5:39pm south of Evansville. The tornado intensified as it tracked to the east of Evansville where it impacted 30 primary residences (2 destroyed, 10 major impacts, 13 minor impacts, 5 affected). Numerous barns and outbuildings were destroyed along the path as it tracked to the northwest of Edgerton. The main EF-2 damage was confined to a stretch from east of Evansville to just southwest of the Yahara River. There was one person in a car that was hit by the tornado that had injuries serious enough to warrant transportation to the…

4. Aug 5, 2000Thunderstorm Wind$5.0 million
   National Weather Service narrative

   This summer's most powerful downburst wind event to affect south-central and southeast Wisconsin pummeled portions of Dane, Green, and Rock counties with damaging hurricane-force winds, large hail, and urban-flood rains. As the 35 mile long line of thunderstorms moved southeast through Dane, northern Green, and Rock Counties, it increased in strength, ultimately producing straight-line winds estimated up to 100 knots (115 mph), heavy rains at a rate of 1 to 3 inches per hour, and hail stones 1 inch in diameter. Due to downed power lines and poles, ultimately about 18,000 customers had electrical power disrupted for 1 to 2 days. Descriptions of weather-related events follow in a…

5. Apr 13, 2006Hail$4.4 million
   National Weather Service narrative

   Wild weather occurred over parts of south-central and southeast Wisconsin on April 13, 2005. Wisconsin's most-costly hailstorm pummeled a large swath from around Mineral Point (Iowa Co.) to north of Milwaukee (Milwaukee Co.), while hurricane-force thunderstorm winds raked parts of Fond du Lac and Sheboygan Counties. Here's what happened: scattered supercells developed in eastern Iowa during the late afternoon hours of April 13th and pushed east-northeastward through southern Wisconsin and northern Illinois during the evening. Three main hailstorms affected southern Wisconsin. The first hailstorm left a swath of hail and hail damage from southern Iowa County (around 1945CST),…

6. Aug 24, 1998Lightning$3.5 million
   National Weather Service narrative

   A cluster of thunderstorms moved east and briefly pulsed to severe weather limits, and dumped large hail over parts of southeastern Wisconsin. Another thunderstorm's lightning struck a 139 year-old historical church in Beloit. The resultant fire destroyed the structure, and it's most of the contents were a total loss.

7. Aug 5, 1998Flash Flood$1.5 million
   National Weather Service narrative

   A series of thunderstorms, slowly moving northeast at 10 mph, trained through the Janesville to Milton area. This round of an additional 1 to 4 inches brought the day's total to 6 to 10 inches based on WSR-88D Doppler radars. The resultant flash flooding damaged the basement contents in about 70 homes, washed out some gravel shoulders on roads, and peeled back the pavement on a couple roads. Water levels on some area streets reached 3 to 4 feet. A 13-year old boy was injured in Janesville's Palmer Park after being swept into a culvert. He was under water for about 9 minutes. One Janesville home was destroyed when its basement wall collapsed. The surging waters busted out windows…

8. Jun 18, 1996Flood, Rock$1.0 million
   National Weather Service narrative

   Thanks to a 3-day rainfall event of 4 to 8 inches on the 16th, 17th, and 18th, across northern Rock county, the Rock River at Afton experienced moderate flooding. The river at this location crested at 10.53 feet at 0630CST on the 25th, or 1.53 feet above flood stage. Widespread flooding of farm land was reported across Rock county. Erosion was a problem as well as blocked roads until water levels receded. Business and resident basement flooding was especially bad in Janesville and Edgerton. Businesses lost money.

9. Jun 1, 2004Flood, Rock$1.0 million
   National Weather Service narrative

   Scattered to widespread heavy rains across south-central and southeast Wisconsin during the period of June 9-12, 2004 kept many rivers and streams at or above flood stage for a good part, or most of the month. Monthly rainfall totals generally ranged from 4 to 7 inches across south-central and southeast Wisconsin, with some scattered spots in Sauk, Columbia, Dodge, Walworth, Racine, and Kenosha Counties picking up 7 to 9.5 inches, or 50 to 100% above normal. In some cases, stretches of some rivers actually went above flood stage in May, 2004. Refer to flood and flash flood events in May, 2004, for additional information. During June, 2004, the high water levels kept much of the…

10. Jun 25, 1998Tornado$845,000
    National Weather Service narrative

    Severe thunderstorms packing winds between 60 and 70 mph and producing hail between 1 and 2 inches in diameter caused significant damage to property and crops. Kenosha and Racine counties experienced some of the worst destruction with 40,000 homes and businesses left without power due to the high number of trees and power lines downed. In the city of Racine a tree fell on a home and another tree crushed an automobile. In Kenosha county, siding was ripped off the side of a Bristol business and metal signs were blown down on Interstate 94. Hidden among the thunderstorms was a lone F2 tornado that took aim on northern Rock county, destroying 3 homes and damaging 4 others. A barn and…

1. Storm Events records before 1996 cover only tornadoes, thunderstorm wind and hail. Damage figures are as reported by the National Weather Service at the time, not adjusted for inflation.

NOAA NCEI Storm Events Database, 1950 to 2026, issued October 26, 2026.

All-time high

110°FJul 14, 1936

All-time low

−29°FJan 31, 2019

Warmest night

90°FJul 21, 1901

Coldest day

−15°FJan 31, 2019

Wettest day

6.55 inJun 24, 1898

Snowiest day

15.0 in2 times, most recently Feb 2, 2011

Hottest year

1931mean 52.9°F

Coldest year

2014mean 43.7°F

Wettest year

193853.90 in

Driest year

190118.98 in

Snowiest season

66.7 in2008-09

Station Beloit (USC00470696), 788 ft elevation, 10.4 miles from the population centre. Daily records from 1893 to October 23, 2026; 98.3% of days in the last 30 years are complete. Records at a single station can differ from a city’s official threaded record, which may combine several stations.

NOAA NCEI Global Historical Climatology Network Daily.

This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).

OpenFEMA Disaster Declarations Summaries, retrieved October 30, 2026. Statewide declarations are not listed.

Neighbouring counties

• Tornadoes NOAA Storm Prediction Center severe weather database, through 2025.
• Tropical cyclones NOAA National Hurricane Center HURDAT2 (Atlantic; Northeast and Central Pacific), through 2025.
• Wildfire USGS/USFS Monitoring Trends in Burn Severity, through 2026.
• Storm events NOAA NCEI Storm Events Database, through 2026.
• Flood insurance OpenFEMA NFIP Redacted Claims v3, refreshed August 4, 2026.
• Declarations OpenFEMA Disaster Declarations Summaries v2, retrieved October 30, 2026.
• Weather records NOAA NCEI Global Historical Climatology Network Daily, station USC00470696.
• River crests NOAA National Weather Service, National Water Prediction Service river gauges, retrieved October 30, 2026.
• Drought NOAA NCEI nClimDiv county Palmer Drought Severity Index, through September 2026.
• Smoke NOAA NESDIS Hazard Mapping System smoke analysis, retrieved October 30, 2026.
• Earthquakes USGS ANSS Comprehensive Earthquake Catalog (ComCat), retrieved October 30, 2026.

Joins, thresholds and known limits are set out in the methodology. Found an error? Report it. Page built October 30, 2026.