Tornadoes · United States · Nebraska · 1986

F4 tornado, Dixon, Dakota, Woodbury and Monona counties, Nebraska and Iowa, July 28, 1986

This F4 tornado ran 52.5 miles across Dixon, Dakota, Woodbury and Monona counties on July 28, 1986, touching down at 6:30 PM CDT and reaching 73 yards wide. It killed nobody and injured 2, and did $50 million to $500 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 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 mphthis tornado

    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
F4
Date
July 28, 1986
Touchdown
6:30 PM CDT (23:30 UTC)
Path length
52.5 miles (84.5 km)
Path width
73 yards (67 m)
Deaths
0
Injuries
2
Property damage
$50 million to $500 million
Counties
Dixon, Dakota, Woodbury and Monona counties
Touchdown point
42.680, -96.970
Lift-off point
42.180, -96.170
Record number
571

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

11.5 hours before the tornado, 125 km from the path. July 28, 1986.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 1986-07-28Temperature 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 -78067, lifted condensation level 3629 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 1986-07-28The 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 110 square meters per square second, 0 to 6 km bulk shear 28 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
-78067 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3629 m above ground
0-6 km bulk shear
28 kt
0-1 km bulk shear
17 kt
0-1 km storm-relative helicity
110 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.0 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

0.5 hours after it, 125 km from the path. July 29, 1986.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 1986-07-29Temperature 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 -93468, lifted condensation level 3613 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 1986-07-29The 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 74 square meters per square second, 0 to 6 km bulk shear 45 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
-93468 J/kg
Surface CAPE
14 J/kg
Mixed-layer LCL
3613 m above ground
0-6 km bulk shear
45 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
7.7 K/km

Open this sounding in Storm Lab

The surface observations

Sioux City (SUX), 16 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
00:00 UTC

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

This ground now

The live radar over the trackEvery 1986 tornado in NebraskaEvery tornado in Nebraska since 1950Warnings in force in Nebraska nowThe forecast where you are

The other tornadoes of July 28, 1986

12 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 285:13 PM CDTF2Brule, SD6.080$50,000 to $500,000
July 285:30 PM CDTF2Aurora, SD3.580$5,000 to $50,000
July 285:50 PM CDTF2Douglas, SD1.980$50,000 to $500,000
July 285:50 PM CDTF1Douglas, SD1.570$5,000 to $50,000
July 286:45 PM CDTF0Union, SD0.240
July 286:50 PM CDTF0Clay, SD0.240
July 287:35 PM CDTF1Clay, IA1.040$50,000 to $500,000
July 287:38 PM CDTF1O'Brien, IA0.113$5,000 to $50,000
July 287:50 PM CDTF0Cedar, NE0.120$50 to $500
July 288:47 PM CDTF2Calhoun, IA4.0150$50,000 to $500,000
July 289:00 PM CDTF0Madison, AL4.0150$50 to $500
July 289:05 PM CDTF0Crawford, IA0.210

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.