Tornadoes · United States · Iowa · 1983

F0 tornado, Louisa County, Iowa, May 1, 1983

This F0 tornado ran 0.1 miles across Louisa County on May 1, 1983, touching down at 8:25 PM CDT and reaching 10 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
May 1, 1983
Touchdown
8:25 PM CDT (01:25 UTC)
Path length
0.1 miles (0.2 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
Property damage
$50 to $500
County
Louisa County
Touchdown point
41.300, -91.500
Record number
213

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), 00:00Z

1.4 hours before the tornado, 174 km from the path. May 2, 1983.

Skew-T log-pSkew-T log-p diagram, Peoria Regional, IL at 00:00Z on 1983-05-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 4 joules per kilogram, CIN -288, lifted condensation level 930 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 1983-05-02The 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 474 square meters per square second, 0 to 6 km bulk shear 73 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
4 J/kg
Mixed-layer CIN
-288 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
930 m above ground
0-6 km bulk shear
73 kt
0-1 km bulk shear
39 kt
0-1 km storm-relative helicity
474 m²/s²
0-3 km storm-relative helicity
538 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.7
0-3 km lapse rate
4.1 K/km

Open this sounding in Storm Lab

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

10.6 hours after it, 174 km from the path. May 2, 1983.

Skew-T log-pSkew-T log-p diagram, Peoria Regional, IL at 12:00Z on 1983-05-02Temperature 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 -3, lifted condensation level 903 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 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 1983-05-02The 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 108 square meters per square second, 0 to 6 km bulk shear 57 knots.1939587897117Sfc1 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
-3 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
903 m above ground
0-6 km bulk shear
57 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
237 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.1 K/km

Open this sounding in Storm Lab

The surface observations

Burlington (BRL), 66 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
00:00 UTC6560130° 10 kt992.9
01:00 UTC6460140° 7 kt992.6
02:00 UTC6557200° 12 kt992.9
03:00 UTC6456330° 10 kt993.2

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

This ground now

The live radar over the trackEvery 1983 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of May 1, 1983

32 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 11:26 PM CDTF1Johnson, NE4.020$5,000 to $50,000
May 12:08 PM CDTF1Miller, MO0.550$50 to $500
May 12:20 PM CDTF1Miller, MO9.077$50,000 to $500,000
May 12:30 PM CDTF2Fremont, IA7.0203$500,000 to $5 million
May 12:30 PM CDTF1Page, IA10.020$50,000 to $500,000
May 12:30 PM CDTF0Page, IA1.020$500 to $5,000
May 12:38 PM CDTF0Cole, MO0.550under $50
May 12:50 PM CDTF1Fremont, NE to IA22.0403$50,000 to $500,000
May 12:55 PM CDTF0Pettis, MO0.350under $50
May 13:10 PM CDTF0Page, IA1.010$50 to $500
May 13:30 PM CDTF3Osage, MO9.04003$500,000 to $5 million
May 13:35 PM CDTF1Gasconade, MO1.050$50 to $500
May 14:55 PM EDTF0Luce, MI0.110$50 to $500
May 14:00 PM CDTF1Taylor, IA2.020$5,000 to $50,000
May 14:30 PM CDTF2Warren, MO0.52003$500,000 to $5 million
May 15:25 PM CDTF1Lincoln, MO0.350$5,000 to $50,000
May 15:30 PM CDTF3Greene, IL4.07715$500,000 to $5 million
May 15:48 PM CDTF1Saint Charles, MO0.350$500 to $5,000
May 16:15 PM CDTF2Jersey, IL0.2171$500,000 to $5 million
May 16:15 PM CDTF2Saint Charles, MO3.0503$500,000 to $5 million
May 16:23 PM CDTF2Jersey, IL0.5771$500,000 to $5 million
May 18:20 PM CDTF3City of Saint Louis, MO to IL16.01,0003$5 million to $50 million
May 19:10 PM CDTF2Saint Clair, IL4.010020$500,000 to $5 million
May 110:25 PM CDTF1Fayette, IL0.333$50,000 to $500,000
May 110:35 PM ESTF0Montgomery, IN0.110$5,000 to $50,000
May 110:45 PM CDTF0Effingham, IL0.2302$50,000 to $500,000
May 111:30 PM CDTF1Wayne, IL0.230$50,000 to $500,000
May 111:45 PM CDTF1Jefferson, IL0.230$500,000 to $5 million
May 11:35 AM EDTF2Lenawee, MI1.9400$5,000 to $50,000
May 11:37 AM EDTF2Lenawee, MI5.9500$5,000 to $50,000
May 11:40 AM EDTF2Lenawee, MI2.0100$5,000 to $50,000
May 11:55 AM EDTF1Monroe, MI3.0100$500 to $5,000

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.