Tornadoes · United States · Iowa · 2005

F3 tornado, Boone, Webster and Hamilton counties, Iowa, November 12, 2005

This F3 tornado ran 17.6 miles across Boone, Webster and Hamilton counties on November 12, 2005, touching down at 4:27 PM CST and reaching 150 yards wide. It killed 1 person and injured 3, and did $12 million of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. F040 to 72 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. F173 to 112 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. F2113 to 157 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. F3158 to 206 mphthis tornado

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. F4207 to 260 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. F5261 to 318 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
F3
Date
November 12, 2005
Touchdown
4:27 PM CST (22:27 UTC)
Path length
17.6 miles (28.3 km)
Path width
150 yards (137 m)
Deaths
1
Injuries
3
Property damage
$12 million
Counties
Boone, Webster and Hamilton counties
Touchdown point
42.170, -94.080
Lift-off point
42.350, -93.880
Record number
1200

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

The county was under a tornado watch, issued at 19:44 UTC and running to 23:56 UTC.

Issued (UTC)ExpiredProductOffice
19:44 UTC23:56 UTCTornado WatchDMX
22:24 UTC23:15 UTCSevere Thunderstorm WarningDMX
22:30 UTC23:00 UTCTornado WarningDMX
22:30 UTC23:00 UTCTornado WarningDMX
03:00 UTC20:03 UTCWind AdvisoryDMX

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 20:16 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Omaha, NE (KOAX), 12:00Z

10.5 hours before the tornado, 224 km from the path. November 12, 2005.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2005-11-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -106103, lifted condensation level 1049 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Omaha, NE at 12:00Z on 2005-11-12The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 155 square meters per square second, 0 to 6 km bulk shear 43 knots.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-106103 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1049 m above ground
0-6 km bulk shear
43 kt
0-1 km bulk shear
30 kt
0-1 km storm-relative helicity
155 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

1.5 hours after it, 224 km from the path. November 13, 2005.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2005-11-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 0 joules per kilogram, CIN -108143, lifted condensation level 1645 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Omaha, NE at 00:00Z on 2005-11-13The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 43 square meters per square second, 0 to 6 km bulk shear 33 knots.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
-108143 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
1645 m above ground
0-6 km bulk shear
33 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
45 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.1 K/km

Open this sounding in Storm Lab

The surface observations

Webster City (EBS), 22 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:35 UTC62.650160° 14 kt995.3
20:40 UTC62.650160° 14 kt995.3
20:55 UTC60.850150° 15 kt994.9
21:00 UTC60.850150° 15 kt994.9
21:15 UTC62.650160° 16 kt994.9
21:20 UTC62.650160° 16 kt994.9
21:35 UTC62.650160° 17 kt21994.2
21:40 UTC62.650160° 17 kt21994.2
21:55 UTC62.650160° 17 kt22993.9
22:00 UTC62.650160° 17 kt22993.9
22:15 UTC62.650140° 15 kt993.2
22:20 UTC62.650140° 15 kt993.2
22:35 UTC60.850140° 18 kt22992.2
22:40 UTC60.850140° 18 kt22992.2
22:55 UTC5946.4170° 19 kt27992.6+RA
23:00 UTC5946.4170° 19 kt27992.6

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Des Moines radar (KDMX), 63 km away, was scanning. The volume nearest the touchdown began at 22:28 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
20:26 UTCTORNADO8 S ScrantonGreene, IADELAYED REPORT FROM NOVEMBER 12TH FROM STORM CHASER VIDEO.
20:26 UTCTORNADO8 S StratfordBoone, IADELAYED REPORT FROM NOVEMBER 12TH FROM STORM CHASER VIDEO.
21:42 UTCHAIL 110 S ScrantonGreene, IA
21:53 UTCHAIL 2.753 Ne Grand JunctionGreene, IAALL SIZES RANGING FROM NICKEL TO BASEBALL. TWO MINUTE HAIL DURATION.
21:56 UTCHAIL 2.53 E DanaGreene, IANINE WINDOWS BROKEN OUT OF HOME DUE TO HAIL.
22:26 UTCHAIL 1WoodwardDallas, IA
22:27 UTCHAIL 0.752 S MinburnDallas, IAON HIGHWAY 169
22:27 UTCTORNADO4 W Pilot MoundBoone, IATORNADO ON GROUND MOVING NORTH
22:28 UTCTORNADO1 Ne MinburnDallas, IAMULTIPLE VORTEX...DELAYED REPORT
22:28 UTCTORNADO1 Ne MinburnDallas, IA
22:28 UTCTORNADO3 W Pilot MoundBoone, IALARGE DEBRIS CLOUD
22:30 UTCTORNADO3 N Pilot MoundBoone, IA
22:31 UTCTORNADO4 Sw WoodwardDallas, IASOUTH OF HIGHWAY 169 AND 141
22:32 UTCTORNADO1 S WoodwardDallas, IAONE MILE SOUTH OF HIGHWAY 141
22:33 UTCTORNADO3 Sw AmesStory, IA
22:33 UTCTORNADO3 Sw StratfordWebster, IA
22:33 UTCTORNADO5 W AmesBoone, IA
22:33 UTCTORNADOWoodwardDallas, IA
22:34 UTCTORNADO1 Sw StratfordWebster, IA
22:35 UTCTORNADO1 W WoodwardDallas, IA
22:36 UTCTORNADO3 S StratfordHamilton, IA
22:36 UTCTORNADOWoodwardDallas, IA100 YD WIDE
22:39 UTCTORNADOWoodwardDallas, IADAMAGE TO CASEYS STORE AND NEARBY BUILDINGS
22:39 UTCTORNADOWoodwardDallas, IA
22:40 UTCTORNADOWoodwardDallas, IAIN A 2 OR 3 BLOCK AREA OF DOWNTOWN WOODWARD 12 OR MORE HOUSES TOTALLY DESTROYED. 1 MINOR INJURY.
22:40 UTCTORNADOWoodwardDallas, IAEXTENSIVE DAMGAGE SOUTH SIDE OF WOODWARD
22:41 UTCTORNADO1 E WoodwardDallas, IA
22:41 UTCTORNADO1 E WoodwardDallas, IAHIGHWAY 210 JUST EAST OF WOODWARD.
22:44 UTCTORNADO1 Ese LutherBoone, IAISU STUDENT
22:44 UTCTORNADO1 Nw MadridBoone, IA
22:45 UTCTORNADO1 N MadridBoone, IAREPORTED BY AMATEUR RADIO.
22:46 UTCTORNADO1 Ne MadridBoone, IA
22:46 UTCTORNADOStratfordHamilton, IA
22:47 UTCTORNADOWoodwardDallas, IAEXTENSIVE DAMGAGE SOUTH SIDE OF WOODWARD
22:49 UTCTORNADO1 E LutherBoone, IAMOVING EAST 100-150 YD WIDE NEAR HIGHWAY 17 AND 300TH ST
22:50 UTCHAIL 0.75Webster CityHamilton, IA
22:53 UTCTORNADO5 W AmesBoone, IA
23:02 UTCTORNADO1 W AmesStory, IAREPORTED BY LAW ENFORCEMENT. JUST NORTH OF HIGHWAY 30.
23:02 UTCTORNADOAmesStory, IA
23:12 UTCTORNADOGilbertStory, IAREPORTED BY STORM CHASER IN THE GILBERT VICINITY.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2005 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of November 12, 2005

13 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
November 123:50 PM CSTF1Greene, IA1.045$10,000
November 124:26 PM CSTF2Dallas, IA14.01002$3.3 million
November 124:30 PM CSTF1Sioux, IA1.0100$800,000
November 124:48 PM CSTF1Boone, IA6.075$200,000
November 124:56 PM CSTF0Story, IA0.230$2,000
November 124:58 PM CSTF2Boone, IA12.01001$350,000
November 125:15 PM CSTF0Story, IA1.650$50,000
November 125:20 PM CSTF1Story, IA8.075$730,000
November 125:27 PM CSTF0Hamilton, IA1.530$10,000
November 125:50 PM CSTF0Hardin, IA0.730$10,000
November 126:40 PM CSTF1Monroe, IA1.550$50,000
November 127:40 PM CSTF1Lawrence, MO5.0751$750,000
November 1210:27 PM CSTF0Polk, AR3.530

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.