Grant County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Grant 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.

Mapped landslides

Mapped by NASA (2).

1. Landslides mapped in the USGS compilation of landslide inventories across the United States (version 3.0, 2025), rated probable or better. The compilation joins inventories made by federal and state agencies for different purposes and areas, so the number mapped in a county reflects how closely it has been surveyed as much as how often its slopes fail. An area with few records may simply not have been mapped. Deaths are as recorded in the inventories; a slide listed in two inventories is counted once.

USGS Landslide Inventories across the United States, version 3.0, retrieved October 27, 2026.

More event types since 1996

Costliest events since 1996

1. Jun 16, 2014Tornado$20.5 million
   National Weather Service narrative

   A tornado formed along a squall line west of Platteville, just south of County Road B, and traveled through Memorial Park on to the Univ. of Wisconsin - Platteville campus. Five people were injured, one of them seriously. There was extensive damage done to five buildings and the stadium on campus. Roofs of two new residential halls were partially destroyed and a third residential hall was also damaged along with one academic building. Two large lighting structures at the football stadium were knocked over, with one crashing across the bleachers causing the concrete foundation underneath the bleachers to be substantially moved. Damage continued into nearby homes and businesses as…

2. Jun 22, 2013Flash Flood$7.1 million
   National Weather Service narrative

   Very heavy rain produced flash flooding across the northeast part of Grant County. |In Boscobel, numerous houses became surrounded by water with evacuations needed, most streets were flooded and cars were under water. 650 homes were impacted by the flood waters with two dozen families displaced. County Roads M and S near Boscobel were impassable due to high water and several other county roads between Blue River and Fennimore were covered with water and impassable. Portions of County Road C southwest of Woodman were under water. The flooding washed out sections of State Highway 133 outside of Woodman and Blue River. Debris was washed down Glass Hollow and Dry Hollow Creeks where…

3. Jun 12, 2008Flash Flood$6.5 million
   National Weather Service narrative

   A major flash flood hit Grant County during the afternoon of June 12th impacting the communities of Lancaster, Potosi, Tennyson, Ellenboro, and other rural areas. Numerous rescues were performed from people trapped in cars, especially in the Potosi area where terrain enhanced the runoff from repeat thunderstorms. Several homes on Hippie Hollow Road in Potosi Township were destroyed along with damage to as many as 600 homes elsewhere in the region. Many highways and county roads suffered flood damage including major bridge and road infrastructure.

4. Jul 18, 2007Flash Flood$2.2 million
   National Weather Service narrative

   Flash flood waters backed up in town as debris blocked area bridges. The water was three to four feet deep in places and propane gas containers began floating on the Mississippi River. Property damage in town was extensive.

5. May 1, 2001Flood, Grant$2.2 million
   National Weather Service narrative

   The Mississippi River crested in April 2001 at levels second only to the all-time flood of record, which occurred in April 1965. Even though water levels were receding, the river remained above flood stage, which continued flooding until the middle of May. High water levels caused damage to homes and businesses, especially in the Prairie du Chien area (Crawford County) and points southward. Due to the extensive damage caused by flood waters, Buffalo, Trempealeau, La Crosse, Vernon, Crawford and Grant County received federal disaster relief funds.

6. Apr 13, 2001Flood, Grant$2.0 million
   National Weather Service narrative

   Heavy rains, combined with snow melt runoff, caused the Mississippi River to reach near record levels. In fact, at most locations the water reached levels second only to the all-time flood of record, which occurred in April 1965. The Mississippi River at La Crosse (La Crosse County) crested at 16.4 feet on April 18, which was the third all-time highest flood on record. Hardest hit was the Prairie du Chien area (Crawford County) and points southward, where flood waters did considerable damage to businesses and homes. Overall damage due to the high water was estimated around 6 million dollars. This resulted in Buffalo, Trempealeau, La Crosse, Vernon, Crawford and Grant County being…

7. Jul 24, 2009Hail$1.8 million
   National Weather Service narrative

   A cluster of severe thunderstorms generated by an approaching cold front affected part of southwest Wisconsin during the afternoon and early evening of July 24. Reports of hail up to golf ball size were common from storm spotters, law enforcement officials and the public. In addition, wind gusts of 60 to 70 mph occurred, although a gust of 78 mph was measured near Dickeyville (Grant County). In Grant County, Wisconsin, residential and business damage included 1000 homes and 200 businesses totaling over 4 million dollars. Agricultural losses could have been as high as 50 million dollars.

8. Jul 24, 2009Thunderstorm Wind$1.5 million
   National Weather Service narrative

   A cluster of severe thunderstorms generated by an approaching cold front affected part of southwest Wisconsin during the afternoon and early evening of July 24. Reports of hail up to golf ball size were common from storm spotters, law enforcement officials and the public. In addition, wind gusts of 60 to 70 mph occurred, although a gust of 78 mph was measured near Dickeyville (Grant County). In Grant County, Wisconsin, residential and business damage included 1000 homes and 200 businesses totaling over 4 million dollars. Agricultural losses could have been as high as 50 million dollars.

9. Jul 24, 2010Flood$1.3 million
   National Weather Service narrative

   The Grant County Emergency Manager reported that U.S. Highway 151 was closed at the SW Road interchange. County Road B was also closed for a while. County Road O sustained substantial damage and was likely closed for around a week. County Road U sustained shoulder damage. Water was also over SW Road near the intersection with Pioneer Road in the southwest part of the city of Platteville. Newspaper articles indicate at least 90 homes throughout the county were damaged by the flooding. Some of the homes had water at least 5 feet above ground level. A two day rainfall total of 9.25 inches was measured at 6 a.m. CST on July 24th in Dickeyville. A three day rainfall total of 8.96…

10. Jun 8, 2008Flash Flood$1.2 million
    National Weather Service narrative

    Highways 35 and 18 were closed due to mudslides and debris. Trees were even being knocked down by the slides.

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

108°FJul 14, 1936

All-time low

−31°F3 times, most recently Feb 3, 1996

Warmest night

85°FJul 10, 1936

Coldest day

−20°FFeb 3, 1996

Wettest day

6.17 inJul 26, 1940

Snowiest day

13.0 in2 times, most recently Jan 3, 1986

Hottest year

1931mean 52.0°F

Coldest year

1996mean 42.9°F

Wettest year

201858.66 in

Driest year

198817.58 in

Snowiest season

90.3 in1925-26

Station Lancaster 4 Wsw (USC00474546), 1,040 ft elevation, 8.9 miles from the population centre. Daily records from 1893 to October 22, 2026; 99.4% 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 USC00474546.
• 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.
• Landslides USGS Landslide Inventories across the United States, version 3.0 (2025).
• 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.