Boone County

Population 26,799 (2025) 571 sq mi

Boone County has recorded 58 tornadoes since 1950, 7th most of 99 counties in Iowa; the most recent was on July 19, 2025.

Hazard fingerprint for Boone County Tornado: 96th percentile. Tropical: 0th percentile. Wildfire: 0th percentile. Flood: 85th percentile. Hail & wind: 77th percentile. Heat: 25th percentile. Cold: 78th percentile. Winter: 64th percentile. TORTROPFIREFLOODSEVEREHEATCOLDWINTER

Hazard fingerprint Each spoke is this county’s percentile among U.S. counties where that hazard occurs. How it is computed

2026
  • Tornado damage paths since 195058

At a glance

The record for Boone County in eight numbers. Each links to its section below.

Tornadoes since 1950

58

7th of 99 in Iowa

66% more than the typical Iowa county

Details

Flood insurance claims

18

55th of 99 in Iowa

$448,000 paid since 2008

Details

Strongest tornado

F5

June 13, 1976, 21.3 mile path

Federal disaster declarations

17

Most recent: Severe Storms, 2020

Details

Record high

111°F

Reached 2 times, most recently July 14, 1936

Details

Record low

−35°F

Reached 4 times, most recently February 4, 1996

Details

Snowiest season

56.3in

Winter of 1961-62

Costliest event since 1996

$12.7M

Drought, August 1, 2003

Details

Tornadoes

About one every 1.3 years since 1950, 5 of them rated F3/EF3 or stronger.

Strongest

June 13, 1976

F5, 21.3 mile path

880 yards wide.

Deadliest

November 12, 2005

1 killed, F3

3 injured along the whole path.

Most recent

Saturday, July 19, 2025

EFU, 4.5 mile path

Within the past year.

Tornadoes by decade Doppler radar era² 1950s: 3 3 1960s: 6 6 1970s: 5 5 1980s: 4 4 1990s: 12 12 2000s: 13 13 2010s: 7 7 2020s: 8 8 1950s1960s1970s1980s1990s2000s2010s2020s
Recorded tornadoes per decade. The 2020s are incomplete.
Tornadoes by month J: 0 F: 0 M: 5 A: 9 M: 12 J: 18 18 J: 5 A: 2 S: 0 O: 1 N: 4 D: 2 JFMAMJJASOND
By month of occurrence, all years.

Every recorded tornado

Tornadoes in Boone County since 1950
Jul 19, 2025EFU4.54000
May 24, 2024EF010.718000
Apr 23, 2022EFU3.96000
Apr 23, 2022EF19.18000
Dec 15, 2021EF216.212500
Dec 15, 2021EF217.712500
May 26, 2020EFU0.22000
May 26, 2020EFU0.62000
Jun 20, 2018EF02.810000
Aug 21, 2017EF03.38000
Mar 6, 2017EF017.98500
Jun 7, 2015EF01.43000
Jun 7, 2015EF02.84000
Aug 31, 2014EF15.015000
May 11, 2014EF01.710000
Nov 12, 2005F212.010010
Nov 12, 2005F16.07500
Nov 12, 2005F317.615031
Nov 12, 2005F214.010020
Jun 11, 2004F00.12500
Jun 11, 2004F00.54000
Apr 17, 2002F00.33500
May 10, 2001F11.05000
Apr 11, 2001F14.04000
Apr 11, 2001F13.014000
Apr 11, 2001F00.72500
Jul 26, 2000F00.22000
May 30, 2000F00.12000
Jun 29, 1998F234.1100850
May 30, 1998F00.23000
May 30, 1998F00.13000
Jun 5, 1995F05.02000
Jun 6, 1994F00.22300
Jul 8, 1993F00.12300
Jun 29, 1993F122.03300
Jun 8, 1993F00.22000
Mar 6, 1992F00.12000
Mar 22, 1991F27.05000
Mar 13, 1990F11.03000
Mar 13, 1990F222.05000
Apr 26, 1989F11.07000
Jul 17, 1982F10.35000
Apr 3, 1981F05.23000
Oct 16, 1980F19.03000
May 4, 1977F10.11000
Jun 13, 1976F30.133300
Jun 13, 1976F24.510000
Jun 13, 1976F521.388090
Jun 13, 1976F317.910000
Jun 29, 1969F20.120000
Jun 16, 1967F11.010000
Jun 11, 1966F22.020000
Jul 7, 1964F22.010000
May 7, 1964F20.16700
May 7, 1962F24.988000
May 10, 1959F441.140010
Apr 4, 1955F211.644000
Jun 7, 1953F12.310000
  1. Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Boone 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.

Hurricanes and tropical storms

No tropical storm or hurricane has tracked within 100 miles since records began in 1851.

Wildfire and smoke

No large wildfire has been mapped here since satellite mapping began in 1984.

Smoke overhead

Smokiest year

2023: 66 days

Heavy smoke on 28 days in 2021, the most of any year.

Last 10 years

28.2 days a year

Medium or heavy smoke, 2016 to 2025.

2025

22 days

Medium or heavy smoke. 41 so far in 2026.

Days with medium or heavy smoke overhead, by year 2011: 12 2012: 23 2013: 24 2014: 12 2015: 22 2016: 3 2017: 9 2018: 21 2019: 10 2020: 30 2021: 55 2022: 24 2023: 66 66 2024: 42 2025: 22 201120122013201420152016201720182019202020212022202320242025
Days each year on which a satellite-traced plume of medium or heavy smoke covered the county’s population centre, 2011 to 2025.
  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.

Floods and flood insurance

18 federal flood insurance claims since 2008, with $448,000 paid.

Federal flood insurance claims by year 2008: 5 5 2010: 5 2008
Claims per year since 2008. Years with fewer than five claims are not shown.

Most claims in one year

2008: 5 claims

$194,000 paid.

2nd most

2010: 5 claims

$194,000 paid.

Claims by ZIP code

Flood insurance claims by ZIP code
5003613$437,000

Flood events since 1996

  • Heavy Rain72
  • Flood38
  • Flash Flood26

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.

Drought

In severe drought or worse for 136 of 1,581 months since 1895 (9%); the longest spell lasted 18 months.

136

Months in severe drought or worse since 1895

51

Months in extreme drought

9%

Share of all months, severe or worse

27

Drought reports to the Weather Service since 1996

Lowest reading

August 1934

−6.64, extreme drought

Longest severe spell

18 months

November 1955 to April 1957.

Latest month

September 2026

+5.55, extremely wet

Last severe month: September 2021.

Months in severe drought or worse, by year 1895: 0 1896: 0 1897: 1 1898: 1 1899: 0 1900: 0 1901: 1 1902: 0 1903: 0 1904: 0 1905: 0 1906: 0 1907: 0 1908: 0 1909: 0 1910: 5 1911: 8 1912: 0 1913: 0 1914: 1 1915: 0 1916: 0 1917: 0 1918: 0 1919: 0 1920: 0 1921: 0 1922: 0 1923: 0 1924: 0 1925: 3 1926: 0 1927: 0 1928: 0 1929: 0 1930: 5 1931: 8 1932: 0 1933: 0 1934: 8 1935: 0 1936: 2 1937: 2 1938: 3 1939: 2 1940: 5 1941: 0 1942: 0 1943: 0 1944: 0 1945: 0 1946: 0 1947: 0 1948: 0 1949: 0 1950: 0 1951: 0 1952: 0 1953: 2 1954: 2 1955: 2 1956: 12 12 1957: 4 1958: 0 1959: 0 1960: 0 1961: 0 1962: 0 1963: 0 1964: 1 1965: 0 1966: 2 1967: 5 1968: 2 1969: 0 1970: 0 1971: 0 1972: 0 1973: 0 1974: 0 1975: 0 1976: 2 1977: 7 1978: 0 1979: 0 1980: 1 1981: 12 1982: 0 1983: 0 1984: 0 1985: 0 1986: 0 1987: 0 1988: 6 1989: 10 1990: 2 1991: 0 1992: 0 1993: 0 1994: 0 1995: 0 1996: 0 1997: 0 1998: 0 1999: 0 2000: 2 2001: 0 2002: 0 2003: 0 2004: 0 2005: 0 2006: 0 2007: 0 2008: 0 2009: 0 2010: 0 2011: 0 2012: 2 2013: 0 2014: 0 2015: 0 2016: 0 2017: 0 2018: 0 2019: 0 2020: 0 2021: 5 2022: 0 2023: 0 2024: 0 2025: 0 18951905191519251935194519551965197519851995200520152025
Months each year with a Palmer index of −3 or lower, 1895 to 2025. Twelve means the whole year.
  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.

Earthquakes

No earthquake of magnitude 2.5 or more is recorded within 50 miles of the county in the USGS catalogue, which begins in 1900.

Severe weather and other events

806 events in the National Weather Service record, 720 of them since 1996.

145

Hail reports, 1 inch or larger

23

Hail, 2 inches or larger

197

Damaging gusts, 58 mph+

90

Winter weather events since 1996

4

Heat events since 1996

28

Cold events since 1996

Largest hail

June 25, 2008

3.00 inches

Strongest measured or estimated gust

August 10, 2020

100 mph

More event types since 1996

Other Storm Events types since 1996
Lightning300Jul 4, 2000

Costliest events since 1996

  1. Aug 1, 2003Drought, Boone$12.7 million
    National Weather Service narrative

    Dry weather settled in over Iowa during the month. The last widespread rain occurred on 09 July. With the increasingly dry conditions became a primary concern as the month progressed. An extended period of heat and humidity from the 15th to 25th saw highs into the 90s to over 100 degrees F. in some locations. By month's end drought indices had worsened to severe to extreme drought across south central Iowa and at least moderate drought over the remainder of the HSA. Waterloo had its driest August on record, Des Moines its 3rd driest and Ottumwa its 8th driest. A cold front brought only a brief respite from the intense heat, as temperatures rebounded into the 90s to near 100…

  2. Nov 12, 2005Tornado$750,000
    National Weather Service narrative

    Tornado moved from Dallas County into Boone County. Two injuries occurred in Woodward.

  3. Oct 26, 1997Heavy Snow, Boone$640,000
    National Weather Service narrative

    The first major winter storm of the season developed over the central Rockies as a powerful upper level jet stream dove into the southern Rockies. Intense low pressure developed over northern Oklahoma, then drifted northeast on the early morning of the 26th. A cold high pressure of Arctic origin was poised to the north of Iowa. The high gradually pushed cold air south into the central U.S. causing the precipitation on the northwest edge of the storm system to change to snow. During the early morning hours, the system went convective with widespread "thundersnow" reported over the south half of Iowa. Lightning struck a tree outside of a house in Nevada causing damage to electrical…

  4. Feb 3, 1997Heavy Snow, Boone$500,000
    National Weather Service narrative

    A low pressure system developed over the southern Rockies during the afternoon of the 2nd and advanced into the southern Plains during the day on the 3rd. There were two centers of low pressure on the afternoon of the 3rd. One was located over western Nebraska, with the second over northern Oklahoma. During the evening of the 3rd, the two merged over Missouri and moved as one unified low pressure northeastward into Illinois. Precipitation developed over western Iowa at first and took the form of mixed freezing rain, ice pellets, and snow. The mixture changed over to snow rather quickly. Farther east, the precipitation remained freezing rain for a longer period over south central…

  5. Dec 23, 2009Ice Storm, Boone$500,000
    National Weather Service narrative

    Part 1 of 2: A major winter storm system affected the central U.S. during Christmas week. There were two upper level systems involved with this storm. The southern stream low dove into the southern U.S. and then turned northeast. The turn was sharper than is typical as the northern stream upper low pushed southeast. The southern stream and polar low interacted with each other, resulting in a Fuji Wara effect. The southern low turned north, then eventually northwest and moved from northern Louisiana into Iowa. This resulted in a considerable amount of warm air being drawn north over Iowa. Cold air remained in place at the surface due to an existing deep snow cover over most of the…

  6. Jun 16, 1996Flash Flood$400,000
  7. Nov 10, 1998High Wind, Boone$300,000
    National Weather Service narrative

    Iowa experienced the worst November storm system since the great storm of 9 and 10 November 1975. During the 9th, low pressure developed over southeast Colorado. The low moved across Kansas during the afternoon and evening of the 9th and deepened to about 990 mb. Warm and moist air was drawn north ahead of the low resulting in widespread across the state. Thunderstorms erupted during the late evening of the 9th, though no severe weather occurred. During the predawn hours of the 10th, a jet streak rotated around the base of the upper level low pressure area. The jet stream, combined with a tropospheric fold, resulted in explosive deepening of the low. As the low moved through…

  8. May 30, 1998Hail$250,000
    National Weather Service narrative

    A very unstable airmass was over Iowa. In spite of the instability, the atmosphere was capped by very warm air aloft. Temperatures at the 700 mb level were between 12 degrees C and 14 degrees C. As a result, thunderstorms had a difficult time forming. The atmosphere was primed with CAPE values in the 4000 to 6000 J/kg range by late morning. Helicity values were near 300 M2/S2. One cell was able to break the cap and became severe. It was a prolific hail producer as well as spawning several tornadoes. Hail reports indicated frequent baseball size hail with a few reports to softball size and larger. The largest report was an incredible 5 inch diameter stone north of Gilbert in Story…

  9. Nov 12, 2005Tornado$250,000
    National Weather Service narrative

    Tornado moved across Boone County and moved into Webster County.

  10. Apr 25, 2007Flood$250,000
    National Weather Service narrative

    A strong low pressure developed over eastern Colorado and moved southeast into northern Oklahoma by the 24th. Deep moisture was pulled north ahead of the low with surface dew points in the low 70s reaching northern Oklahoma. Strong isentropic lift took place over the Des Moines CWA and resulted in a large and sustained area of rain and embedded thunderstorms. Rainfall of two to over five inches of rainfall occurred over a large part of the CWA, with isolated amounts in the six to seven inch range over a 2 day period. This event brought about the flash flooding event of the evening of the 24th. The situation transitioned into a general areal flood event on the 25th, with several…

  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.

Weather records

From Boone, 1.1 miles from the county’s population centre, with records from 1905.

All-time high
111°F2 times, most recently Jul 14, 1936
All-time low
−35°F4 times, most recently Feb 4, 1996
Warmest night
85°FAug 6, 1918
Coldest day
−17°FJan 6, 1912
Wettest day
6.06 inJul 9, 1993
Snowiest day
14.0 inNov 30, 1928
Hottest year
1931mean 52.7°F
Coldest year
1924mean 44.4°F
Wettest year
199355.87 in
Driest year
193019.59 in
Snowiest season
56.3 in1961-62
Average monthly high and low temperature and precipitation, last 30 years, Boone 32°F 29° 10° 1.2 Jan 34° 13° 1.4 Feb 47° 26° 2.3 Mar 61° 37° 3.9 Apr 71° 48° 5.3 May 81° 59° 5.5 Jun 84° 63° 4.8 Jul 82° 61° 4.7 Aug 77° 53° 3.2 Sep 64° 40° 3.1 Oct 48° 27° 1.9 Nov 34° 16° 1.6 Dec Precipitation, inches
Average daily high and low by month, and average monthly precipitation, over the last 30 years.
Nights at or below freezing per year 1976: 171 1977: 146 1978: 152 1979: 162 1981: 167 1982: 156 1983: 167 1984: 174 1985: 155 1986: 158 1987: 159 1988: 167 1989: 177 177 1990: 157 1991: 159 1992: 154 1993: 165 1994: 145 1995: 151 1996: 169 1997: 162 1998: 132 1999: 146 2000: 141 2001: 138 2002: 163 2003: 154 2004: 148 2005: 152 2006: 153 2007: 152 2008: 165 2009: 155 2010: 138 2011: 158 2012: 139 2013: 170 2014: 151 2015: 142 2016: 135 2017: 141 2018: 164 2019: 158 2020: 164 2021: 145 2022: 168 2023: 157 2024: 143 2025: 137 19761987199720072017
Nights at or below freezing each complete year, last 50 years. Thirty-year average: 151.3.
Snowfall by winter 1976: 12.9 in 1977: 37.6 in 1978: 47.3 in 1979: 26.0 in 1980: 10.2 in 1981: 36.7 in 1982: 44.3 in 1983: 36.4 in 1984: 31.3 in 1985: 25.5 in 1986: 19.0 in 1987: 21.2 in 1988: 12.2 in 1989: 14.0 in 1990: 36.1 in 1991: 23.6 in 1992: 31.1 in 1993: 38.4 in 1994: 25.5 in 1995: 41.4 in 1996: 44.1 in 1997: 55.8 in 1998: 39.6 in 1999: 24.9 in 2000: 40.6 in 2001: 17.6 in 2002: 31.8 in 2003: 52.5 in 2004: 23.4 in 2005: 35.3 in 2006: 46.4 in 2007: 38.6 in 2008: 38.5 in 2009: 56.1 in 56.1 2010: 33.4 in 2014: 29.2 in 2015: 37.2 in 2016: 19.2 in 2017: 33.9 in 2018: 38.0 in 2019: 19.6 in 2020: 43.9 in 2021: 23.1 in 2023: 30.2 in 2024: 22.7 in 2025: 31.5 in 19761986199620062019
Total snowfall each winter (July to June), last 50 winters.

Median first snow

November 23

Earliest: October 10, 1932

Median last snow

March 29

Latest: May 28, 1947

0 of 105 winters had no measurable snow.

Station Boone (USC00130807), 1,035 ft elevation, 1.1 miles from the population centre. Daily records from 1905 to October 27, 2026; 98.9% 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.

Federal disaster declarations

17 since 1953. The most recent: Severe Storms, August 17, 2020.

Federal disaster declarations
Aug 17, 2020Severe StormSevere StormsMajor disasterDR-4557-IA
Mar 23, 2020BiologicalCovid-19 PandemicMajor disasterDR-4483-IA
Mar 13, 2020BiologicalCovid-19EmergencyEM-3480-IA
Mar 23, 2019FloodSevere Storms and FloodingMajor disasterDR-4421-IA
Jul 29, 2010Severe StormSevere Storms, Flooding, and TornadoesMajor disasterDR-1930-IA
Mar 2, 2010Severe StormSevere Winter StormMajor disasterDR-1880-IA
May 27, 2008Severe StormSevere Storms, Tornadoes, and FloodingMajor disasterDR-1763-IA
Sep 14, 2007Severe StormSevere Storms and FloodingMajor disasterDR-1727-IA
Mar 14, 2007Severe StormSevere Winter StormsMajor disasterDR-1688-IA
Sep 10, 2005HurricaneHurricane Katrina EvacuationEmergencyEM-3239-IA
May 25, 2004Severe StormSevere Storms, Tornadoes, and FloodingMajor disasterDR-1518-IA
Jul 2, 1998FloodSevere Storms, Tornadoes and FloodingMajor disasterDR-1230-IA
Aug 21, 1996Severe StormSevere Storms, and FloodingMajor disasterDR-1133-IA
Jul 9, 1993FloodSevere Storms & FloodingMajor disasterDR-996-IA
Dec 26, 1991Severe Ice StormIce StormMajor disasterDR-928-IA
May 26, 1990FloodSevere Storms & FloodingMajor disasterDR-868-IA
Apr 22, 1965FloodFloodingMajor disasterDR-193-IA

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.

How this compares

Where Boone County stands among 99 counties in Iowa and 3,143 in the United States.

Ranks
Tornadoes since 1950587 / 99278 / 3,143
Tornadoes rated F3/EF3 or stronger514 / 99242 / 3,143
Tropical cyclones within 50 mi0——
Hurricane-strength passes within 50 mi0——
Wildfire acres since 19840——
Flood insurance claims1855 / 992,103 / 3,143
Flood insurance paid$448,00045 / 991,829 / 3,143
Disaster declarations1770 / 992,018 / 3,143
Flood events since 199613624 / 99341 / 3,143
Hail and wind events since 199639217 / 99757 / 3,143
Winter storm events since 19969058 / 991,092 / 3,143
Reported damage since 1996$24.9 million56 / 991,303 / 3,143
River crests at major flood stage0——
High tide flooding days a year, last 10 years0.0——
Months in severe drought since 189513687 / 991,287 / 3,143
Medium or heavy smoke days a year, last 10 years28.238 / 99332 / 3,143
Earthquakes M4+ within 50 mi since 19000——
Earthquakes M2.5+ in the county since 19730——

Neighbouring counties

Neighbouring counties
Dallas County600042
Greene County35004
Hamilton County560028
Polk County70001,550
Story County6600286
Webster County630093

Sources and vintage

Every number on this page comes from these public records.

  • 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 USC00130807.
  • 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.