Tornadoes · United States · Kentucky · 1968

F4 tornado, Calloway, Marshall, Trigg and Caldwell counties, Kentucky, April 3, 1968

This F4 tornado ran 50.6 miles across Calloway, Marshall, Trigg and Caldwell counties on April 3, 1968, touching down at 11:50 PM GMT-6 and reaching 100 yards wide. It killed 2 people and injured 30, and did $500,000 to $5 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
April 3, 1968
Touchdown
11:50 PM GMT-6 (05:50 UTC)
Path length
50.6 miles (81.4 km)
Path width
100 yards (91 m)
Deaths
2
Injuries
30
Property damage
$500,000 to $5 million
Counties
Calloway, Marshall, Trigg and Caldwell counties
Touchdown point
36.630, -88.300
Lift-off point
37.120, -87.630
Record number
67

What the Weather Service recorded

The deaths

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

AgeSexWhereKind
Direct
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.

Nashville Metro, TN (KBNA), 00:00Z

5.8 hours before the tornado, 147 km from the path. April 4, 1968.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 1968-04-04Temperature 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 -6584, lifted condensation level 836 meters above ground. Wind barbs in knots down the right edge.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Nashville Metro, TN at 00:00Z on 1968-04-04The 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 350 square meters per square second, 0 to 6 km bulk shear 58 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
0 J/kg
Mixed-layer CIN
-6584 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
836 m above ground
0-6 km bulk shear
58 kt
0-1 km bulk shear
36 kt
0-1 km storm-relative helicity
350 m²/s²
0-3 km storm-relative helicity
395 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.7 K/km

Open this sounding in Storm Lab

Nashville Metro, TN (KBNA), 12:00Z

6.2 hours after it, 147 km from the path. April 4, 1968.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 1968-04-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 38 joules per kilogram, CIN -24, lifted condensation level 764 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Nashville Metro, TN at 12:00Z on 1968-04-04The 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 449 square meters per square second, 0 to 6 km bulk shear 69 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
38 J/kg
Mixed-layer CIN
-24 J/kg
Surface CAPE
65 J/kg
Mixed-layer LCL
764 m above ground
0-6 km bulk shear
69 kt
0-1 km bulk shear
43 kt
0-1 km storm-relative helicity
449 m²/s²
0-3 km storm-relative helicity
549 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.9 K/km

Open this sounding in Storm Lab

This ground now

The live radar over the trackEvery 1968 tornado in KentuckyEvery tornado in Kentucky since 1950Warnings in force in Kentucky nowThe forecast where you are

The other tornadoes of April 3, 1968

21 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 312:10 AM GMT-6F2Noble, OK15.9100$5,000 to $50,000
April 312:15 AM GMT-6F2Noble, OK4.71001$5,000 to $50,000
April 33:20 PM GMT-6F2O'Brien, IA0.5100$5,000 to $50,000
April 33:20 PM GMT-6F1Cherokee, IA0.5200under $50
April 33:45 PM GMT-6F2Texas, MO11.9100$500 to $5,000
April 34:00 PM GMT-6F2Jasper, IA5.2150$5,000 to $50,000
April 36:00 PM GMT-6F1Jefferson, MO7.6100$5,000 to $50,000
April 36:05 PM GMT-6F2Monroe, IL19.850$50,000 to $500,000
April 36:20 PM GMT-6F4Lincoln, AR33.7400516$50,000 to $500,000
April 36:40 PM GMT-6F1Clinton, IL8.350$50,000 to $500,000
April 37:05 PM GMT-6F2Madison, MO12.8500$50,000 to $500,000
April 37:15 PM GMT-6F2DeSoto, MS15.2104
April 37:20 PM GMT-6F0Arkansas, AR0.3200$500 to $5,000
April 37:30 PM GMT-6F2Jefferson, AR0.5200
April 37:30 PM GMT-6F2Bollinger, MO2.550$5,000 to $50,000
April 37:44 PM GMT-6F3Greene, AR3.610016$500,000 to $5 million
April 37:50 PM GMT-6F2Arkansas, AR0.1101$500 to $5,000
April 38:30 PM GMT-6F1Williamson, IL0.5100$5,000 to $50,000
April 39:00 PM GMT-6F2Crittenden, AR14.910015$5,000 to $50,000
April 39:35 PM GMT-6F1Dyer, TN0.110
April 39:45 PM GMT-6F3Shelby, TN28.81,760432$500,000 to $5 million

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.