Tornadoes · United States · Kentucky · 1991

F2 tornado, Barren County, Kentucky, April 9, 1991

This F2 tornado ran 0.5 miles across Barren County on April 9, 1991, touching down at 1:45 PM CDT and reaching 400 yards wide. It killed nobody and injured 3, 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 mphthis tornado

    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
F2
Date
April 9, 1991
Touchdown
1:45 PM CDT (18:45 UTC)
Path length
0.5 miles (0.8 km)
Path width
400 yards (366 m)
Deaths
0
Injuries
3
Property damage
$500,000 to $5 million
County
Barren County
Touchdown point
36.970, -85.870
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.

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

6.8 hours before the tornado, 114 km from the path. April 9, 1991.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 12:00Z on 1991-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1517 joules per kilogram, CIN -34, lifted condensation level 637 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, Nashville Metro, TN at 12:00Z on 1991-04-09The 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 178 square meters per square second, 0 to 6 km bulk shear 30 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
1517 J/kg
Mixed-layer CIN
-34 J/kg
Surface CAPE
1009 J/kg
Mixed-layer LCL
637 m above ground
0-6 km bulk shear
30 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
178 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.9
Supercell composite
4.9
0-3 km lapse rate
4.6 K/km

Open this sounding in Storm Lab

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

5.2 hours after it, 114 km from the path. April 10, 1991.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 1991-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 112 joules per kilogram, CIN -165, lifted condensation level 1015 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, Nashville Metro, TN at 00:00Z on 1991-04-10The 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 31 square meters per square second, 0 to 6 km bulk shear 44 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
112 J/kg
Mixed-layer CIN
-165 J/kg
Surface CAPE
126 J/kg
Mixed-layer LCL
1015 m above ground
0-6 km bulk shear
44 kt
0-1 km bulk shear
22 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
46 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

The surface observations

Bowling Green (BWG), 49 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
00:00 UTC

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

This ground now

The live radar over the trackEvery 1991 tornado in KentuckyEvery tornado in Kentucky since 1950Warnings in force in Kentucky nowThe forecast where you are

The other tornadoes of April 9, 1991

24 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
April 911:00 AM CDTF0Madison, TN0.310$500 to $5,000
April 912:50 PM CDTF2Todd, KY18.0300$500,000 to $5 million
April 92:45 PM EDTF1Kenton, KY3.0100$50,000 to $500,000
April 93:00 PM EDTF1Madison, KY4.050$5,000 to $50,000
April 93:00 PM EDTF1Rockcastle, KY2.0100$50,000 to $500,000
April 93:45 PM EDTF0Chautauqua, NY0.510$5,000 to $50,000
April 94:15 PM EDTF1Erie, NY0.510$5,000 to $50,000
April 95:30 PM EDTF1Livingston, NY0.530$50,000 to $500,000
April 92:50 PM PDTF0Kitsap, WA0.830$5,000 to $50,000
April 96:20 PM EDTF0Braxton, WV0.140$500 to $5,000
April 94:30 PM PDTF0Multnomah, OR0.210$50 to $500
April 98:15 PM EDTF0Brevard, FL0.110
April 98:30 PM EDTF1Westmoreland, PA0.2504$5,000 to $50,000
April 98:40 PM EDTF1Bedford, PA0.5100$5,000 to $50,000
April 98:40 PM EDTF1Bedford, PA1.0100$50,000 to $500,000
April 99:00 PM EDTF1Cambria, PA1.0100$50,000 to $500,000
April 96:15 PM PDTF2Bonner, ID1.0100$50,000 to $500,000
April 99:18 PM EDTF1Cambria, PA2.0100$50,000 to $500,000
April 99:20 PM EDTF1Fayette, PA0.550$50,000 to $500,000
April 99:30 PM EDTF1Cambria, PA0.550$500 to $5,000
April 99:50 PM EDTF0Centre, PA0.560$5,000 to $50,000
April 910:00 PM EDTF1Bedford, PA0.550$5,000 to $50,000
April 910:30 PM EDTF1Cumberland, PA0.4203$50,000 to $500,000
April 910:30 PM EDTF0Cumberland, PA3.020$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.