Tornadoes · United States · South Dakota · 1986

F1 tornado, Codington County, South Dakota, July 29, 1986

This F1 tornado ran 5.9 miles across Codington County on July 29, 1986, touching down at 11:04 PM CDT and reaching 100 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 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
July 29, 1986
Touchdown
11:04 PM CDT (04:04 UTC)
Path length
5.9 miles (9.5 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
County
Codington County
Touchdown point
44.900, -97.280
Lift-off point
44.920, -97.100
Record number
583

The warnings

12 minutes of warning. NWS ABR issued a tornado warning for this county at 03:52 UTC, 12 minutes before the tornado touched down, in force until 04:30 UTC.

Issued (UTC)ExpiredProductOffice
03:19 UTC04:15 UTCSevere Thunderstorm WarningABR
03:52 UTC04:30 UTCTornado WarningABR
04:21 UTC05:00 UTCTornado WarningABR
04:58 UTC05:30 UTCTornado WarningABR

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 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.

Aberdeen, SD (KHON), 00:00Z

4.1 hours before the tornado, 95 km from the path. July 30, 1986.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 00:00Z on 1986-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 3602 joules per kilogram, CIN -50, lifted condensation level 1336 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, Aberdeen, SD at 00:00Z on 1986-07-30The 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 103 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
3602 J/kg
Mixed-layer CIN
-50 J/kg
Surface CAPE
4502 J/kg
Mixed-layer LCL
1336 m above ground
0-6 km bulk shear
45 kt
0-1 km bulk shear
16 kt
0-1 km storm-relative helicity
103 m²/s²
0-3 km storm-relative helicity
243 m²/s²
Significant tornado parameter
3.5
Supercell composite
24.1
0-3 km lapse rate
6.8 K/km

Open this sounding in Storm Lab

Aberdeen, SD (KHON), 12:00Z

7.9 hours after it, 95 km from the path. July 30, 1986.

Skew-T log-pSkew-T log-p diagram, Aberdeen, SD at 12:00Z on 1986-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 188 joules per kilogram, CIN -272, lifted condensation level 941 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, Aberdeen, SD at 12:00Z on 1986-07-30The 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 126 square meters per square second, 0 to 6 km bulk shear 49 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
188 J/kg
Mixed-layer CIN
-272 J/kg
Surface CAPE
95 J/kg
Mixed-layer LCL
941 m above ground
0-6 km bulk shear
49 kt
0-1 km bulk shear
11 kt
0-1 km storm-relative helicity
126 m²/s²
0-3 km storm-relative helicity
446 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.9
0-3 km lapse rate
4.2 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1986 tornado in South DakotaEvery tornado in South Dakota since 1950Warnings in force in South Dakota nowThe forecast where you are

The other tornadoes of July 29, 1986

3 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
July 296:45 PM CDTF1Holt, NE5.070$500 to $5,000
July 297:25 PM CDTF1Antelope, NE3.020$5,000 to $50,000
July 299:49 PM CDTF0Stutsman, ND0.213

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.