Tornadoes · United States · Iowa · 1966

F1 tornado, Ringgold County, Iowa, May 23, 1966

This F1 tornado ran 0.3 miles across Ringgold County on May 23, 1966, touching down at 7:30 AM GMT-5 and reaching 50 yards wide. It killed nobody, and did under $50 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 23, 1966
Touchdown
7:30 AM GMT-5 (12:30 UTC)
Path length
0.3 miles (0.5 km)
Path width
50 yards (46 m)
Deaths
0
Injuries
0
Property damage
under $50
County
Ringgold County
Touchdown point
40.830, -94.330
Record number
190

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

0.5 hours before the tornado, 179 km from the path. May 23, 1966.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 1966-05-23Temperature 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 -40207, lifted condensation level 3643 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 1966-05-23The 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 216 square meters per square second, 0 to 6 km bulk shear 57 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
0 J/kg
Mixed-layer CIN
-40207 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3643 m above ground
0-6 km bulk shear
57 kt
0-1 km bulk shear
32 kt
0-1 km storm-relative helicity
216 m²/s²
0-3 km storm-relative helicity
418 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

Omaha, NE (KOAX), 00:00Z

11.5 hours after it, 179 km from the path. May 24, 1966.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 00:00Z on 1966-05-24Temperature 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 -60438, lifted condensation level 3575 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 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 1966-05-24The 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 -76 square meters per square second, 0 to 6 km bulk shear 62 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
-60438 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
3575 m above ground
0-6 km bulk shear
62 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
-76 m²/s²
0-3 km storm-relative helicity
-45 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.3 K/km

Open this sounding in Storm Lab

The surface observations

Des Moines (DSM), 97 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
11:00 UTC68.564130° 12 kt1001
12:00 UTC6765140° 5 kt1001-TSRA
13:00 UTC676610° 13 ktTS SHRA
14:00 UTC636230° 10 kt1006.4TS SHRA

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

This ground now

The live radar over the trackEvery 1966 tornado in IowaEvery tornado in Iowa since 1950Warnings in force in Iowa nowThe forecast where you are

The other tornadoes of May 23, 1966

23 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 237:00 AM GMT-5F2Atchison, MO5.750$5,000 to $50,000
May 232:00 PM GMT-5F2Dodge, WI4.3503$50,000 to $500,000
May 233:30 PM GMT-5F2Dallas, TX0.1333$5,000 to $50,000
May 233:45 PM GMT-5F0Howard, MO0.110under $50
May 234:30 PM GMT-5F2Muscatine, IA4.9350$50,000 to $500,000
May 235:00 PM GMT-5F2Des Moines, IA4.1100$50,000 to $500,000
May 235:00 PM GMT-5F1Fannin, TX0.113
May 235:00 PM GMT-5F1Fannin, TX0.123
May 235:00 PM GMT-5F1Fannin, TX1.513
May 235:00 PM GMT-5F1Fannin, TX0.513
May 235:00 PM GMT-5F0Fannin, TX1.513
May 235:00 PM GMT-5F0Fannin, TX0.413
May 235:30 PM GMT-5F2Scott, IA2.0250$5,000 to $50,000
May 235:45 PM GMT-5F1Callaway, MO1.550$5,000 to $50,000
May 236:00 PM GMT-5F2Callaway, MO2.0100$5,000 to $50,000
May 236:10 PM GMT-5F3Hunt, TX2.01005$5,000 to $50,000
May 236:10 PM GMT-5F1Hunt, TX2.050
May 236:10 PM GMT-5F0Hunt, TX2.060
May 237:00 PM GMT-5F1Fulton, IL2.0100$50,000 to $500,000
May 237:00 PM GMT-5F2Wood, TX3.033
May 239:13 PM GMT-5F0Stutsman, ND0.110
May 239:45 PM GMT-5F1Van Buren, MI0.333$500 to $5,000
May 2310:40 PM GMT-5F2Zavala, TX16.0133

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.