Tornadoes · United States · Missouri · 1984

F4 tornado, Harrison, Decatur, Wayne, Lucas and Monroe counties, Missouri and Iowa, June 7, 1984

This F4 tornado ran 134.0 miles across Harrison, Decatur, Wayne, Lucas and Monroe counties on June 7, 1984, touching down at 6:45 PM CDT and reaching 250 yards wide. It killed 3 people and injured 64, and did $5 million to $50 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
June 7, 1984
Touchdown
6:45 PM CDT (23:45 UTC)
Path length
134.0 miles (215.6 km)
Path width
250 yards (229 m)
Deaths
3
Injuries
64
Property damage
$5 million to $50 million
Counties
Harrison, Decatur, Wayne, Lucas and Monroe counties
Touchdown point
40.420, -94.030
Lift-off point
41.580, -91.850
Record number
495

What the Weather Service recorded

The deaths

1 direct deaths are recorded for this tornado, each with what Storm Data knows of it.

AgeSexWhereKind
Direct

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

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.

Peoria Regional, IL (KPIA), 12:00Z

11.8 hours before the tornado, 283 km from the path. June 7, 1984.

Skew-T log-pSkew-T log-p diagram, Peoria Regional, IL at 12:00Z on 1984-06-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 105 joules per kilogram, CIN -230, lifted condensation level 1044 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, Peoria Regional, IL at 12:00Z on 1984-06-07The 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 174 square meters per square second, 0 to 6 km bulk shear 29 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
105 J/kg
Mixed-layer CIN
-230 J/kg
Surface CAPE
176 J/kg
Mixed-layer LCL
1044 m above ground
0-6 km bulk shear
29 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
174 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

Peoria Regional, IL (KPIA), 00:00Z

0.2 hours after it, 283 km from the path. June 8, 1984.

Skew-T log-pSkew-T log-p diagram, Peoria Regional, IL at 00:00Z on 1984-06-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 611 joules per kilogram, CIN -55, lifted condensation level 1065 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, Peoria Regional, IL at 00:00Z on 1984-06-08The 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 154 square meters per square second, 0 to 6 km bulk shear 37 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
611 J/kg
Mixed-layer CIN
-55 J/kg
Surface CAPE
1140 J/kg
Mixed-layer LCL
1065 m above ground
0-6 km bulk shear
37 kt
0-1 km bulk shear
32 kt
0-1 km storm-relative helicity
154 m²/s²
0-3 km storm-relative helicity
246 m²/s²
Significant tornado parameter
0.5
Supercell composite
4.2
0-3 km lapse rate
6.1 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1984 tornado in MissouriEvery tornado in Missouri since 1950Warnings in force in Missouri nowThe forecast where you are

The other tornadoes of June 7, 1984

40 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
June 71:55 AM CDTF2Avoyelles Parish, LA1.01003$50,000 to $500,000
June 73:45 PM CDTF1Woodbury, IA7.0100$50,000 to $500,000
June 74:14 PM CDTF2Cherokee, IA10.077$500,000 to $5 million
June 73:30 PM MDTF0Grant, ND0.310
June 74:33 PM CDTF2Brown, KS18.03005$500,000 to $5 million
June 74:42 PM CDTF2Ida, IA16.01501$500,000 to $5 million
June 74:43 PM CDTF2Cass, IA23.01508$500,000 to $5 million
June 75:04 PM CDTF1O'Brien, IA6.077$50,000 to $500,000
June 75:10 PM CDTF2Ida, IA12.01001$500,000 to $5 million
June 75:12 PM CDTF2Buena Vista, IA4.01003$500,000 to $5 million
June 75:17 PM CDTF2Pocahontas, IA25.01002$500,000 to $5 million
June 75:20 PM CDTF3Page, IA25.01003$500,000 to $5 million
June 75:23 PM CDTF1Clay, IA1.077$50,000 to $500,000
June 75:30 PM CDTF2Clay, IA2.077$50,000 to $500,000
June 75:37 PM CDTF0Ward, ND0.510
June 76:00 PM CDTF2Pocahontas, IA8.0100$500,000 to $5 million
June 76:15 PM CDTF2Humboldt, IA22.0150$500,000 to $5 million
June 76:15 PM CDTF3Kossuth, IA9.01505$5 million to $50 million
June 76:29 PM CDTF2Kossuth, IA21.01501$500,000 to $5 million
June 76:45 PM CDTF2Hancock, IA18.0127$500,000 to $5 million
June 76:59 PM CDTF0Wells, ND0.510
June 77:00 PM CDTF1Pawnee, NE0.350$500 to $5,000
June 77:15 PM CDTF1Freeborn, MN6.080$50,000 to $500,000
June 77:19 PM CDTF3Freeborn, MN14.010012$5 million to $50 million
June 77:20 PM CDTF1Waseca, MN1.050$500 to $5,000
June 77:25 PM CDTF1Freeborn, MN18.080$500,000 to $5 million
June 77:36 PM CDTF2Mower, MN5.01007$500,000 to $5 million
June 77:54 PM CDTF1Lucas, IA0.550$5,000 to $50,000
June 78:15 PM CDTF1Olmsted, MN1.050$50,000 to $500,000
June 78:35 PM CDTF0Goodhue, MN2.550$5,000 to $50,000
June 78:45 PM CDTF2Ringgold, IA14.015013$500,000 to $5 million
June 79:33 PM CDTF1Wayne, IA0.550$5,000 to $50,000
June 79:33 PM CDTF2Keokuk, IA24.02001$500,000 to $5 million
June 710:00 PM CDTF2Chippewa, WI12.0150$50,000 to $500,000
June 710:00 PM CDTF2Miner, SD0.160$50,000 to $500,000
June 710:30 PM CDTF2Daviess, MO1.0100$50,000 to $500,000
June 711:00 PM CDTF2Daviess, MO3.01001$500,000 to $5 million
June 711:30 PM CDTF1Price, WI1.050$5,000 to $50,000
June 712:30 AM CDTF2Lafayette, WI11.040$50,000 to $500,000
June 712:41 AM CDTF5Barneveld tornado, WI36.04509200$50,000 to $500,000

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.