Tornadoes · United States · Iowa · 2006

F0 tornado, Union County, Iowa, March 30, 2006

This F0 tornado ran 0.2 miles across Union County on March 30, 2006, touching down at 5:57 PM CST and reaching 30 yards wide. It killed nobody, and did $40,000 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 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
March 30, 2006
Touchdown
5:57 PM CST (23:57 UTC)
Path length
0.2 miles (0.3 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
Property damage
$40,000
County
Union County
Touchdown point
41.070, -94.420
Lift-off point
41.070, -94.420
Record number
189

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 20:15 UTC and running to 01:55 UTC.

Issued (UTC)ExpiredProductOffice
20:15 UTC01:55 UTCTornado WatchDMX
21:10 UTC21:31 UTCSevere Thunderstorm WarningDMX
23:40 UTC00:07 UTCSevere Thunderstorm WarningDMX
00:00 UTC00:30 UTCTornado WarningDMX

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 0.10 chance of a tornado within 25 miles. The outlook in force was issued at 19:42 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

12.0 hours before the tornado, 166 km from the path. March 30, 2006.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2006-03-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 34 joules per kilogram, CIN -342, lifted condensation level 611 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 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 2006-03-30The 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 322 square meters per square second, 0 to 6 km bulk shear 30 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
34 J/kg
Mixed-layer CIN
-342 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
611 m above ground
0-6 km bulk shear
30 kt
0-1 km bulk shear
38 kt
0-1 km storm-relative helicity
322 m²/s²
0-3 km storm-relative helicity
310 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.8 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

0.0 hours before the tornado, 166 km from the path. March 31, 2006.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 2006-03-31Temperature 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 -103504, lifted condensation level 992 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 2006-03-31The 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 135 square meters per square second, 0 to 6 km bulk shear 57 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
-103504 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
992 m above ground
0-6 km bulk shear
57 kt
0-1 km bulk shear
29 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.6 K/km

Open this sounding in Storm Lab

The radar

The Des Moines radar (KDMX), 94 km away, was scanning. The volume nearest the touchdown began at 23:57 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
23:20 UTCTSTM WND GST 6011 N CorningAdams, IASHERIFFS OFFICE REPORTS WIND ESTIMATE 60 TO 70 MPH NEAR MOUNT ETNA. DELAYED REPORT.
23:20 UTCTSTM WND GST 60MassenaCass, IA60 MPH WINDS AN PEA SIZED HAIL.
23:22 UTCTSTM WND GST 604 Se New MarketTaylor, IA
23:25 UTCTSTM WND GST 601 W BedfordTaylor, IA60 MPH WIND AND PEA SIZED HAIL REPORTED BY AMATEUR RADIO OPERATOR.
23:30 UTCTSTM WND GST 71FontanelleAdair, IA71 MPH WINDS MEASURED BY MESONET.
23:30 UTCTSTM WND GST 71FontanelleAdair, IA
23:35 UTCTSTM WND DMG9 N FontanelleAdair, IADAMAGE TO CATTLE SHED AND BARN DAMAGE.
23:40 UTCTSTM WND DMGCaseyGuthrie, IASIX SEMI TRUCKS BLOWN OFF I-80 BETWEEN MILE MARKERS 83-86. POSSIBLE INJURIES. TIME ESTIMATED.
23:44 UTCTSTM WND DMG4 E AdairAdair, IA4 SEMIS BLOWN OFF INTERSTATE 80 WEST OF MENLO.
23:45 UTCTSTM WND GST 60CrestonUnion, IA
23:45 UTCTSTM WND GST 60CrestonUnion, IA60 MPH WIND AND PEA SIZED HAIL.
23:55 UTCTSTM WND GST 602 W Mount AyrRinggold, IA
23:56 UTCTSTM WND DMG7 Ssw EarlhamMadison, IA1 FOOT DIAMETER MAPLE TREE LIMB BROKEN OFF TREE. DELAYED REPORT.
23:57 UTCTORNADO3 W CrestonUnion, IA
00:00 UTCTORNADO4 W Creston AirportUnion, IATORNADO REPORTED BRIEF TOUCHDOWN.

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 March 30, 2006

25 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
March 301:25 PM CSTF0Reno, KS3.050$80,000
March 302:13 PM CSTF1Marion, KS6.0751$70,000
March 302:18 PM CSTF0Stephens, OK0.550
March 302:23 PM CSTF0Butler, NE0.5440
March 302:29 PM CSTF0Colfax, NE0.5440
March 303:35 PM CSTF0Saunders, NE0.3100$50,000
March 303:50 PM CSTF0Wilson, KS2.550
March 303:55 PM CSTF0Woodbury, IA0.5100$100,000
March 304:00 PM CSTF0Sarpy, NE3.0150
March 304:04 PM CSTF1Brown, KS3.0100$350,000
March 304:06 PM CSTF2Montgomery, KS16.01251$1.0 million
March 305:35 PM CSTF1Wilson, KS10.075$20,000
March 306:00 PM CSTF0Woodson, KS0.150
March 306:00 PM CSTF0Union, IA0.125
March 306:03 PM CSTF0Allen, KS0.550
March 306:04 PM CSTF0Dallas, IA0.125
March 307:10 PM CSTF2Andrew, MO5.08008$800,000
March 307:15 PM CSTF0Cooke, TX0.115
March 308:10 PM CSTF0Harrison, MO1.050
March 308:20 PM CSTF0Johnson, MO9.050$10,000
March 308:28 PM CSTF1Pettis, MO13.6751$450,000
March 308:30 PM CSTF0Grayson, TX0.115
March 308:36 PM CSTF0Grayson, TX0.110$10,000
March 3010:55 PM CSTF1Pike, IL4.5200
March 3011:10 PM CSTF1Pike, IL2.7250

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.