Tornadoes · United States · Iowa · 1989

F1 tornado, Wayne County, Iowa, May 24, 1989

This F1 tornado ran 2.0 miles across Wayne County on May 24, 1989, touching down at 8:32 PM CDT and reaching 20 yards wide. It killed nobody, and did $5,000 to $50,000 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 mph

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

  2. F173 to 112 mphthis tornado

    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
F1
Date
May 24, 1989
Touchdown
8:32 PM CDT (01:32 UTC)
Path length
2.0 miles (3.2 km)
Path width
20 yards (18 m)
Deaths
0
Injuries
0
Property damage
$5,000 to $50,000
County
Wayne County
Touchdown point
40.780, -93.530
Record number
346

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
01:31 UTC02:30 UTCSevere Thunderstorm 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 High Risk. The outlook in force was issued at 07:38 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), 00:00Z

1.5 hours before the tornado, 246 km from the path. May 25, 1989.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 1989-05-25Temperature 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 -56313, lifted condensation level 3561 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 1989-05-25The 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 -63 square meters per square second, 0 to 6 km bulk shear 39 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
-56313 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3561 m above ground
0-6 km bulk shear
39 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
-63 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
7.1 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 12:00Z

10.5 hours after it, 246 km from the path. May 25, 1989.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 1989-05-25Temperature 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 -101334, lifted condensation level 3602 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 1989-05-25The 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 -100 square meters per square second, 0 to 6 km bulk shear 81 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
-101334 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3602 m above ground
0-6 km bulk shear
81 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
-100 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
3.9 K/km

Open this sounding in Storm Lab

The surface observations

Lamoni (LWD), 35 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
00:00 UTC8072190° 10 kt995.9
02:00 UTC7168360° 6 kt998.3
03:00 UTC7065350° 10 kt1000.7

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

This ground now

The live radar over the trackEvery 1989 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of May 24, 1989

30 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 248:55 AM CDTF0Linn, MO0.210
May 244:06 PM CDTF1Sibley, MN6.040
May 245:50 PM EDTF0Broward, FL0.210
May 245:24 PM CDTF0Nicollet, MN0.110
May 245:45 PM CDTF0Nicollet, MN0.313
May 246:11 PM CDTF4Adams, IA49.01,760$5 million to $50 million
May 246:20 PM CDTF4Hamilton, IA66.0150$5 million to $50 million
May 246:30 PM CDTF0Adams, WI0.550$5,000 to $50,000
May 246:30 PM CDTF0Nicollet, MN0.110under $50
May 246:47 PM CDTF0Freeborn, MN0.110
May 246:53 PM CDTF0Freeborn, MN0.110
May 247:03 PM CDTF0Freeborn, MN0.313
May 247:03 PM CDTF0Steele, MN0.110
May 247:10 PM CDTF1Freeborn, MN0.120
May 247:30 PM CDTF0Green Lake, WI0.123
May 248:25 PM CDTF2Harrison, MO2.573$500,000 to $5 million
May 248:30 PM CDTF0Chippewa, WI0.150$5,000 to $50,000
May 248:30 PM CDTF1Harrison, MO1.050$50,000 to $500,000
May 248:40 PM CDTF0Marshall, IA0.250$500 to $5,000
May 248:45 PM CDTF1Chickasaw, IA10.033$5,000 to $50,000
May 249:10 PM CDTF1Winnebago, WI1.250$50,000 to $500,000
May 249:30 PM CDTF0Clayton, IA0.323$50,000 to $500,000
May 2410:05 PM CDTF1Calumet, WI0.350$50,000 to $500,000
May 2410:15 PM CDTF0Manitowoc, WI0.250$5,000 to $50,000
May 2410:25 PM CDTF0Fond du Lac, WI0.250$5,000 to $50,000
May 249:40 PM MDTF0Bonneville, ID1.060$500 to $5,000
May 2411:10 PM CDTF1Dodge, WI1.573$50,000 to $500,000
May 2411:25 PM CDTF1Dodge, WI2.273$50,000 to $500,000
May 2412:10 AM CDTF0Milwaukee, WI0.123$50,000 to $500,000
May 241:43 AM EDTF1Newaygo, MI0.650$5,000 to $50,000

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.