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 Each spoke is this county’s percentile among U.S. counties where that hazard occurs. How it is computed
- Tornado damage paths since 195058
At a glance
The record for Boone County in eight numbers. Each links to its section below.
Strongest tornado
F5
June 13, 1976, 21.3 mile path
Snowiest season
56.3in
Winter of 1961-62
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.
Every recorded tornado
| Jul 19, 2025 | EFU | 4.5 | 0 | 0 |
| May 24, 2024 | EF0 | 10.7 | 0 | 0 |
| Apr 23, 2022 | EFU | 3.9 | 0 | 0 |
| Apr 23, 2022 | EF1 | 9.1 | 0 | 0 |
| Dec 15, 2021 | EF2 | 16.2 | 0 | 0 |
| Dec 15, 2021 | EF2 | 17.7 | 0 | 0 |
| May 26, 2020 | EFU | 0.2 | 0 | 0 |
| May 26, 2020 | EFU | 0.6 | 0 | 0 |
| Jun 20, 2018 | EF0 | 2.8 | 0 | 0 |
| Aug 21, 2017 | EF0 | 3.3 | 0 | 0 |
| Mar 6, 2017 | EF0 | 17.9 | 0 | 0 |
| Jun 7, 2015 | EF0 | 1.4 | 0 | 0 |
| Jun 7, 2015 | EF0 | 2.8 | 0 | 0 |
| Aug 31, 2014 | EF1 | 5.0 | 0 | 0 |
| May 11, 2014 | EF0 | 1.7 | 0 | 0 |
| Nov 12, 2005 | F2 | 12.0 | 1 | 0 |
| Nov 12, 2005 | F1 | 6.0 | 0 | 0 |
| Nov 12, 2005 | F3 | 17.6 | 3 | 1 |
| Nov 12, 2005 | F2 | 14.0 | 2 | 0 |
| Jun 11, 2004 | F0 | 0.1 | 0 | 0 |
| Jun 11, 2004 | F0 | 0.5 | 0 | 0 |
| Apr 17, 2002 | F0 | 0.3 | 0 | 0 |
| May 10, 2001 | F1 | 1.0 | 0 | 0 |
| Apr 11, 2001 | F1 | 4.0 | 0 | 0 |
| Apr 11, 2001 | F1 | 3.0 | 0 | 0 |
| Apr 11, 2001 | F0 | 0.7 | 0 | 0 |
| Jul 26, 2000 | F0 | 0.2 | 0 | 0 |
| May 30, 2000 | F0 | 0.1 | 0 | 0 |
| Jun 29, 1998 | F2 | 34.1 | 85 | 0 |
| May 30, 1998 | F0 | 0.2 | 0 | 0 |
| May 30, 1998 | F0 | 0.1 | 0 | 0 |
| Jun 5, 1995 | F0 | 5.0 | 0 | 0 |
| Jun 6, 1994 | F0 | 0.2 | 0 | 0 |
| Jul 8, 1993 | F0 | 0.1 | 0 | 0 |
| Jun 29, 1993 | F1 | 22.0 | 0 | 0 |
| Jun 8, 1993 | F0 | 0.2 | 0 | 0 |
| Mar 6, 1992 | F0 | 0.1 | 0 | 0 |
| Mar 22, 1991 | F2 | 7.0 | 0 | 0 |
| Mar 13, 1990 | F1 | 1.0 | 0 | 0 |
| Mar 13, 1990 | F2 | 22.0 | 0 | 0 |
| Apr 26, 1989 | F1 | 1.0 | 0 | 0 |
| Jul 17, 1982 | F1 | 0.3 | 0 | 0 |
| Apr 3, 1981 | F0 | 5.2 | 0 | 0 |
| Oct 16, 1980 | F1 | 9.0 | 0 | 0 |
| May 4, 1977 | F1 | 0.1 | 0 | 0 |
| Jun 13, 1976 | F3 | 0.1 | 0 | 0 |
| Jun 13, 1976 | F2 | 4.5 | 0 | 0 |
| Jun 13, 1976 | F5 | 21.3 | 9 | 0 |
| Jun 13, 1976 | F3 | 17.9 | 0 | 0 |
| Jun 29, 1969 | F2 | 0.1 | 0 | 0 |
| Jun 16, 1967 | F1 | 1.0 | 0 | 0 |
| Jun 11, 1966 | F2 | 2.0 | 0 | 0 |
| Jul 7, 1964 | F2 | 2.0 | 0 | 0 |
| May 7, 1964 | F2 | 0.1 | 0 | 0 |
| May 7, 1962 | F2 | 4.9 | 0 | 0 |
| May 10, 1959 | F4 | 41.1 | 1 | 0 |
| Apr 4, 1955 | F2 | 11.6 | 0 | 0 |
| Jun 7, 1953 | F1 | 2.3 | 0 | 0 |
- Injuries and deaths are for the tornado’s whole path, which may extend beyond the county. Deaths recorded within Boone County: 0.
- 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.
- 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.
Most claims in one year
2008: 5 claims
$194,000 paid.
2nd most
2010: 5 claims
$194,000 paid.
Claims by ZIP code
| 50036 | 13 | $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.
- 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
| Lightning | 3 | 0 |
Costliest events since 1996
- 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…
- Nov 12, 2005Tornado$750,000
National Weather Service narrative
Tornado moved from Dallas County into Boone County. Two injuries occurred in Woodward.
- 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…
- 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…
- 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…
- Jun 16, 1996Flash Flood$400,000
- 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…
- 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…
- Nov 12, 2005Tornado$250,000
National Weather Service narrative
Tornado moved across Boone County and moved into Webster County.
- 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…
- 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
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.
| Aug 17, 2020 | Severe Storm | DR-4557-IA |
| Mar 23, 2020 | Biological | DR-4483-IA |
| Mar 13, 2020 | Biological | EM-3480-IA |
| Mar 23, 2019 | Flood | DR-4421-IA |
| Jul 29, 2010 | Severe Storm | DR-1930-IA |
| Mar 2, 2010 | Severe Storm | DR-1880-IA |
| May 27, 2008 | Severe Storm | DR-1763-IA |
| Sep 14, 2007 | Severe Storm | DR-1727-IA |
| Mar 14, 2007 | Severe Storm | DR-1688-IA |
| Sep 10, 2005 | Hurricane | EM-3239-IA |
| May 25, 2004 | Severe Storm | DR-1518-IA |
| Jul 2, 1998 | Flood | DR-1230-IA |
| Aug 21, 1996 | Severe Storm | DR-1133-IA |
| Jul 9, 1993 | Flood | DR-996-IA |
| Dec 26, 1991 | Severe Ice Storm | DR-928-IA |
| May 26, 1990 | Flood | DR-868-IA |
| Apr 22, 1965 | Flood | DR-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.
| Tornadoes since 1950 | 58 | 7 / 99 |
| Tornadoes rated F3/EF3 or stronger | 5 | 14 / 99 |
| Tropical cyclones within 50 mi | 0 | — |
| Hurricane-strength passes within 50 mi | 0 | — |
| Wildfire acres since 1984 | 0 | — |
| Flood insurance claims | 18 | 55 / 99 |
| Flood insurance paid | $448,000 | 45 / 99 |
| Disaster declarations | 17 | 70 / 99 |
| Flood events since 1996 | 136 | 24 / 99 |
| Hail and wind events since 1996 | 392 | 17 / 99 |
| Winter storm events since 1996 | 90 | 58 / 99 |
| Reported damage since 1996 | $24.9 million | 56 / 99 |
| River crests at major flood stage | 0 | — |
| High tide flooding days a year, last 10 years | 0.0 | — |
| Months in severe drought since 1895 | 136 | 87 / 99 |
| Medium or heavy smoke days a year, last 10 years | 28.2 | 38 / 99 |
| Earthquakes M4+ within 50 mi since 1900 | 0 | — |
| Earthquakes M2.5+ in the county since 1973 | 0 | — |
Neighbouring counties
| Dallas County | 60 | 0 |
| Greene County | 35 | 0 |
| Hamilton County | 56 | 0 |
| Polk County | 70 | 0 |
| Story County | 66 | 0 |
| Webster County | 63 | 0 |
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.