Boone County

Every recorded tornado

1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Boone County: 25.
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.

Every earthquake of magnitude 4 or more within 50 miles

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. Nov 22, 2010Tornado$4.5 million
   National Weather Service narrative

   A tornado which touched down in eastern Winnebago County, crossed into western Boone County and moved across largely open rural fields towards the town of Caledonia. Significant damage occurred to at least six buildings in Caledonia, with approximately 20 additional buildings sustaining minor damage. Several large trees were snapped or uprooted, and a grain bin partially collapsed. The tornado was again likely at EF2 intensity at this time. The tornado then continued northeast from Caledonia, downing several power poles and causing damage ranging from blown off roofs to completely destroying at least three farm outbuildings. One of these buildings, located two miles northwest of…

2. Jan 7, 2008Tornado$2.0 million
   National Weather Service narrative

   A tornado touched down at 330 pm CST about 1.2 miles north of Poplar Grove in Boone County and ended at 348 pm about 3.2 miles north northeast of Harvard in McHenry County. The tornado crossed the Boone McHenry County line near Hunter Road, about 3 miles northeast of Capron. The first signs of damage were at Quail Trap Road just east of Poplar Grove Road where trees were damaged and sections of roofing were removed from a shed. The tornado intensified to EF2 intensity at Edwards Apple Orchard on Centerville Road. A large barn was destroyed and other buildings were severely damaged. Large trees were snapped or uprooted. The tornado reached its maximum intensity of EF3 at the…

3. Aug 25, 2006Thunderstorm Wind$400,000
   National Weather Service narrative

   Huge trees and 40 to 50 power lines blown down. A roof was blown off a house and a semi trailer was blown over.

4. Apr 12, 2014Hail$250,000
   National Weather Service narrative

   Hail to two inches in diameter was estimated on Route 76 near Poplar Grove Airport. Shopping centers in the area reported heavy damage from hail. A Walmart had 129 skylights damaged or broken while a ShopKo was also damaged by the hail.

5. Apr 9, 2015Tornado$150,000
   National Weather Service narrative

   Witnesses said the tornado touched down in a field then moved northeast destroying a detached garage. The tornado ripped the roof off of a home though the walls mainly remained intact. Several hardwood trees were snapped. Maximum wind speeds were estimated to be 110 mph. (Tornado 6 of 7).

6. May 17, 2017Tornado$100,000
   National Weather Service narrative

   A tornado touched down approximately two miles south of Poplar Grove. Tree branches were broken on Poplar Grove Road where the tornado touched down. A large softwood tree trunk was snapped on Beaver Road. Trees were debarked on Beaverton Road. A small outbuilding was destroyed on Edson Road. Hardwood trees were snapped at the trunk on Russellville Road and again on Capron Road. On the east side of Capron, A garage was destroyed and shingles were peeled off the north side of a home and dozens of trees were snapped. Another small outbuilding was destroyed on County Line Road with debris strewn about three quarters of a mile downstream. The tornado passed into McHenry County on…

7. Jun 28, 2017Flash Flood$100,000
   National Weather Service narrative

   Very heavy rain fell across Boone County during the evening hours of June 28th. Numerous roads were flooded, closed and impassable due to flash flooding. Many county roads were also flooded and closed. Significant flooding was reported on many roads in Belvidere where there were water rescues from stranded vehicles. Ditches were overflowing onto Genoa Road. Storm total rainfall reports included 4.95 inches 2 miles northwest of Belvidere and 4.70 inches in Belvidere.

8. Aug 7, 2007Flash Flood$100,000
   National Weather Service narrative

   Several roads and many basements were flooded after 4 to 6 inches of rain fell over southern Boone County in a short period of time. Motorists flooded on Appleton Road near Route 20.

9. Apr 9, 2015Tornado$75,000
   National Weather Service narrative

   This is a continuation of a tornado that began in Dekalb County. This tornado was identified from a storm chaser video and survey. Three barns were destroyed on Pearl Street Road. Maximum winds speeds were estimated to be 110 mph. (Tornado 4b of 7).

10. Oct 26, 2010High Wind, Boone$50,000
    National Weather Service narrative

    Record setting low pressure over Minnesota produced high winds across northern Illinois on October 26, behind a strong cold front which swept across the state during the morning. The high winds caused around 200,000 Commonwealth Edison customers to lose power. Five hundred flights were canceled at O'Hare Airport. The high winds blew down tree limbs and power lines across northern Illinois. ||Some peak wind gusts included; 71 mph near Dixon in Lee County, 62 mph at Waukegan Airport in Lake County, and 58 mph at Peru in LaSalle County. ||Damage reports included; 448 reports of trees damaged in Chicago as well as many traffic lights, street lights and poles; wind blew a cargo…

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

105°FJul 7, 2012

All-time low

−31°FJan 31, 2019

Warmest night

80°FJul 19, 2019

Coldest day

−14°FJan 18, 1994

Wettest day

5.70 inAug 14, 1987

Snowiest day

11.7 inNov 25, 2018

Hottest year

2012mean 53.2°F

Coldest year

1979mean 45.4°F

Wettest year

197356.48 in

Driest year

197623.25 in

Snowiest season

74.5 in1978-79

Station Rockford Gtr Rockford Airport (USW00094822), 725 ft elevation, 14.2 miles from the population centre. Daily records from 1951 to October 26, 2026; 100.0% 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 USW00094822.
• 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.