Tornadoes · United States · Iowa · 1993

F0 tornado, Osceola County, Iowa, June 29, 1993

This F0 tornado ran 0.2 miles across Osceola County on June 29, 1993, touching down at 3:31 PM CDT and reaching 23 yards wide. It killed nobody, and did $50 to $500 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
June 29, 1993
Touchdown
3:31 PM CDT (20:31 UTC)
Path length
0.2 miles (0.3 km)
Path width
23 yards (21 m)
Deaths
0
Injuries
0
Property damage
$50 to $500
County
Osceola County
Touchdown point
43.450, -95.770
Record number
628

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

Issued (UTC)ExpiredProductOffice
21:25 UTC23:45 UTCFlash Flood WarningFSD
21:40 UTC23:45 UTCFlash Flood WarningFSD
23:30 UTC02:00 UTCFlash Flood WarningFSD

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. The outlook in force was issued at 08:49 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.

Minneapolis, MN (KSTC), 12:00Z

8.5 hours before the tornado, 233 km from the path. June 29, 1993.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 1993-06-29Temperature 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 -12743, lifted condensation level 938 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, Minneapolis, MN at 12:00Z on 1993-06-29The 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 109 square meters per square second, 0 to 6 km bulk shear 43 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
-12743 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
938 m above ground
0-6 km bulk shear
43 kt
0-1 km bulk shear
13 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
211 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
0.9 K/km

Open this sounding in Storm Lab

Minneapolis, MN (KSTC), 00:00Z

3.5 hours after it, 233 km from the path. June 30, 1993.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 1993-06-30Temperature 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 -10045, lifted condensation level 679 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, Minneapolis, MN at 00:00Z on 1993-06-30The 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 177 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
-10045 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
679 m above ground
0-6 km bulk shear
42 kt
0-1 km bulk shear
18 kt
0-1 km storm-relative helicity
177 m²/s²
0-3 km storm-relative helicity
311 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
2.6 K/km

Open this sounding in Storm Lab

The surface observations

Worthington (OTG), 28 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
19:00 UTC70.8861110° 16 kt251009.8
20:00 UTC6961.88100° 17 kt261007.8
21:00 UTC656190° 38 kt451005.1
22:00 UTC635960° 21 kt241009.1

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

This ground now

The live radar over the trackEvery 1993 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of June 29, 1993

16 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 295:00 AM CDTF0Newton, MO0.5231$5,000 to $50,000
June 2911:50 AM CDTF3Lawrence, WY to SD3.0150$500 to $5,000
June 291:10 PM EDTF0Hall, GA4.023$50 to $500
June 294:35 PM CDTF1Tripp, SD20.073$50 to $500
June 294:50 PM CDTF2Tripp, SD5.0100$5,000 to $50,000
June 295:55 PM CDTF0Kossuth, IA0.230$500 to $5,000
June 296:45 PM CDTF0Pocahontas, IA0.120$50 to $500
June 296:45 PM CDTF2Pocahontas, IA15.070$50,000 to $500,000
June 298:15 PM CDTF0Calhoun, IA0.230$500 to $5,000
June 298:44 PM CDTF0Greene, IA0.230$500 to $5,000
June 299:00 PM CDTF0Greene, IA0.223$500 to $5,000
June 299:15 PM CDTF0Crawford, IA0.123$500 to $5,000
June 299:27 PM CDTF1Boone, IA22.033$5,000 to $50,000
June 2910:15 PM CDTF0Adair, IA0.120$50 to $500
June 2911:11 PM CDTF1Scott, IA0.4232$5,000 to $50,000
June 2911:23 PM CDTF0Scott, IA0.120$50 to $500

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.