Tornadoes · United States · Iowa · 2006

F0 tornado, Davis County, Iowa, April 2, 2006

This F0 tornado ran 0.2 miles across Davis County on April 2, 2006, touching down at 3:47 PM CDT and reaching 30 yards wide. It killed nobody.

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 mphthis tornado

    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 mph

    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
F0
Date
April 2, 2006
Touchdown
3:47 PM CDT (20:47 UTC)
Path length
0.2 miles (0.3 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Davis County
Touchdown point
40.720, -92.450
Lift-off point
40.720, -92.450
Record number
211

The warnings

25 minutes of warning. NWS DMX issued a tornado warning for this county at 20:22 UTC, 25 minutes before the tornado touched down, in force until 21:00 UTC.

The county was under a tornado watch, issued at 17:29 UTC and running to 01:00 UTC.

Issued (UTC)ExpiredProductOffice
17:29 UTC01:00 UTCTornado WatchDMX
20:02 UTC20:40 UTCSevere Thunderstorm WarningDMX
20:22 UTC21:00 UTCTornado WarningDMX
20:57 UTC21:15 UTCTornado WarningDMX
03:00 UTC08:36 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 Moderate Risk, with a 0.10 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 19:55 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.

Davenport, (KDVN), 12:00Z

8.8 hours before the tornado, 191 km from the path. April 2, 2006.

Skew-T log-pSkew-T log-p diagram, Davenport, at 12:00Z on 2006-04-02Temperature 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 -100942, lifted condensation level 903 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, Davenport, at 12:00Z on 2006-04-02The 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 246 square meters per square second, 0 to 6 km bulk shear 42 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
-100942 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
903 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
25 kt
0-1 km storm-relative helicity
246 m²/s²
0-3 km storm-relative helicity
257 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
1.3 K/km

Open this sounding in Storm Lab

Davenport, (KDVN), 00:00Z

3.2 hours after it, 191 km from the path. April 3, 2006.

Skew-T log-pSkew-T log-p diagram, Davenport, at 00:00Z on 2006-04-03Temperature 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 -89592, lifted condensation level 978 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, Davenport, at 00:00Z on 2006-04-03The 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 -180 square meters per square second, 0 to 6 km bulk shear 20 knots.193958Sfc1 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
-89592 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
978 m above ground
0-6 km bulk shear
20 kt
0-1 km bulk shear
39 kt
0-1 km storm-relative helicity
-180 m²/s²
0-3 km storm-relative helicity
-19 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

The surface observations

Ottumwa (OTM), 42 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
18:53 UTC5956130° 10 kt1000.7
19:53 UTC6257130° 11 kt999.7
20:04 UTC62.657.2120° 11 kt999
20:24 UTC64.459120° 10 kt998.6
20:35 UTC62.657.2130° 9 kt998.6
20:53 UTC6359110° 8 kt998.3TS
21:04 UTC62.659120° 10 kt998VCTS +RA BR
21:10 UTC62.65990° 8 kt997.6VCTS RA BR
21:13 UTC62.659 5 kt997.6VCTS -RA BR
21:20 UTC62.65990° 7 kt997VCTS
21:31 UTC60.85980° 8 kt996.6
21:53 UTC6259150° 7 kt996.6TS
22:03 UTC62.659170° 7 kt996.6
22:26 UTC64.457.2230° 21 kt24996.3VCTS
22:42 UTC64.451.8220° 24 kt36996.3

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

The radar

The Des Moines radar (KDMX), 155 km away, was scanning. The volume nearest the touchdown began at 20:48 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
20:10 UTCHAIL 0.755 Nw CentervilleAppanoose, IA
20:47 UTCTORNADO3 Sw BloomfieldDavis, IABRIEF TOUCHDOWN
20:57 UTCTORNADO4 N PulaskiDavis, IA
20:57 UTCTORNADO7 N PulaskiDavis, IA
21:03 UTCTSTM WND GST 505 E Mount SterlingVan Buren, IAALSO PEA SIZED HAIL
21:04 UTCHAIL 0.255 Nw KeosauquaVan Buren, IA
21:05 UTCTSTM WND DMG5 N KeosauquaVan Buren, IA2 LARGE TREES UPROOTED. ROOF BLOWN OF BARN.
21:08 UTCTORNADO 22 W KeosauquaVan Buren, IA3 MILE DAMAGE PATH. 2 HOMES UNROOFED. TREES SNAPPED AND UPROOTED. POWER POLES DOWN. OUTBUILDINGS DESTROYED.
21:15 UTCTORNADO 16 S FairfieldJefferson, IABARN DESTROYED AND TREES DOWN.
21:15 UTCTORNADO2 W KeosauquaVan Buren, IATIME ESTIMATED 400-415 PM. MODERATE DAMAGE TO HOME AND BARN DESTROYED AT 194 27 KING AVENUE NEAR PITTSBURG.
21:15 UTCTORNADO4 S FairfieldJefferson, IATREE DOWN AND MAILBOXES DOWN IN FAIRFIELD. 4 MILES SOUTH OF TOWN BARN DESTROYED.
21:20 UTCHAIL 0.5FairfieldJefferson, IAONE INCH OF HAIL COVERING GROUND
21:20 UTCTORNADO 11 N Mount ZionVan Buren, IAGARAGE UNROOFED. TREES DAMAGED. MACHINE SHED DESTROYED.
21:24 UTCTORNADO 11 E StockportVan Buren, IAOUTBUILDINGS AND TREES DAMAGED ALONG A 3 MILE PATH.
21:28 UTCHAIL 0.25FairfieldJefferson, IANUMEROUS REPORTS OF PEA SIZE HAIL LASTING MORE THAN 5 MINUTES. HAIL ACCUMULATION UP TO ONE INCH DEEP.
21:30 UTCTORNADO1 E StockportVan Buren, IA

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

This ground now

The live radar over the trackEvery 2006 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of April 2, 2006

66 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 23:57 PM CDTF0Davis, IA0.125
April 24:03 PM CDTF2Van Buren, IA3.0100$30,000
April 24:15 PM CDTF1Van Buren, IA2.050$10,000
April 24:18 PM CDTF1Jefferson, IA0.350$10,000
April 24:19 PM CDTF1Van Buren, IA3.050$10,000
April 24:25 PM CDTF2Ralls, MO3.5350
April 24:46 PM CDTF2Washington, IA1.075$30,000
April 24:59 PM CDTF1Sharp, AR9.5100$100,000
April 25:00 PM CDTF0Saint Francois, MO0.150
April 25:00 PM CDTF1Washington, IA0.150$10,000
April 25:05 PM CDTF0Sainte Genevieve, MO2.040
April 25:06 PM CDTF0Warren, IA0.230
April 25:15 PM CDTF2Saint Clair, IL7.0100111
April 25:15 PM CDTF0Macoupin, IL2.030
April 25:15 PM CDTF0Macoupin, IL0.530
April 25:16 PM CDTF0Henderson, IL0.025
April 25:20 PM CDTF1McDonough, IL12.0233$150,000
April 25:21 PM CDTF0Madison, IL16.050
April 25:30 PM CDTF1Madison, IL2.0100
April 25:31 PM CDTF0Polk, IA0.230
April 25:35 PM CDTF0Macoupin, IL0.120
April 25:37 PM CDTF3Randolph, AR to MO77.08802177$86 million
April 25:41 PM CDTF0Montgomery, IL1.050
April 25:46 PM CDTF1Sangamon, IL0.5200
April 25:49 PM CDTF1Sangamon, IL2.0100
April 25:50 PM CDTF2Montgomery, IL20.0200
April 25:56 PM CDTF1Sangamon, IL1.0100
April 25:56 PM CDTF1Montgomery, IL2.2100
April 25:58 PM CDTF1Sangamon, IL1.0100
April 25:59 PM CDTF0Sangamon, IL1.350
April 26:00 PM CDTF2White, AR6.3100
April 26:06 PM CDTF1Sangamon, IL0.850
April 26:08 PM CDTF1Christian, IL6.33001
April 26:13 PM CDTF1Sangamon, IL1.51001
April 26:14 PM CDTF1Christian, IL6.0150
April 26:17 PM CDTF0Christian, IL0.150
April 26:20 PM CDTF1Christian, IL1.0100
April 26:22 PM CDTF0Menard, IL0.340
April 26:29 PM CDTF3Woodruff, AR38.05005$5.0 million
April 26:30 PM CDTF0Macon, IL0.130
April 26:30 PM CDTF2Macon, IL4.5300
April 26:32 PM CDTF0Logan, IL1.080
April 26:36 PM CDTF0Logan, IL2.550
April 26:36 PM CDTF1Macon, IL7.51503
April 26:42 PM CDTF0Cumberland, IL0.8100
April 26:43 PM CDTF0Scott, MO1.550$20,000
April 27:01 PM CDTF0DeWitt, IL0.130
April 27:08 PM CDTF0McLean, IL0.130
April 27:12 PM CDTF0McLean, IL0.550
April 27:13 PM CDTF1McLean, IL1.050
April 27:15 PM CDTF0Champaign, IL0.130
April 27:22 PM CDTF0McLean, IL2.650
April 27:25 PM CDTF0Champaign, IL0.350
April 27:31 PM CDTF0Ballard, KY0.130
April 27:32 PM CDTF3Dyer, TN18.08801670$20 million
April 29:07 PM EDTF1Lawrence, IN0.5100$100,000
April 28:09 PM CDTF3Gibson, TN31.0880644$27 million
April 29:25 PM EDTF1Tippecanoe, IN0.5100$50,000
April 29:37 PM EDTF1Jackson, IN0.5100$200,000
April 28:43 PM CDTF3Gibson, TN8.088026$15 million

All 67 of them

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.