Tornadoes · United States · Indiana · 2002

F3 tornado, Ellettsville to Southport, Indiana, September 20, 2002

From Ellettsville to Southport, this F3 tornado ran 112.0 miles across Monroe, Morgan, Johnson and Marion counties on September 20, 2002, touching down at 12:59 PM EST and reaching 150 yards wide. It killed nobody and injured 127, and did $103 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 mphthis tornado

    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
F3
Date
September 20, 2002
Touchdown
12:59 PM EST (17:59 UTC)
Path length
112.0 miles (180.2 km)
Path width
150 yards (137 m)
Deaths
0
Injuries
127
Property damage
$103 million
Counties
Monroe, Morgan, Johnson and Marion counties
Touchdown point
39.230, -86.620
Lift-off point
40.500, -85.300
Record number
850

What the Weather Service recorded

One of Indiana's longest tracking tornados formed along a squall line on the morning of September 20. The tornado touched down near Ellettsville in Monroe county and then remained on the ground for 112 miles before lifting in Blackford county. The tornado produced F3 damage at its strongest points. Nearly 100 single family homes were destroyed, along with several mobile homes. Some apartments were also destroyed. Many businesses and hundreds of homes received damage. Several counties were declared disaster areas.

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

The warnings

20 minutes of warning. NWS IND issued a tornado warning for this county at 17:39 UTC, 20 minutes before the tornado touched down, in force until 18:15 UTC.

Issued (UTC)ExpiredProductOffice
17:39 UTC18:15 UTCTornado WarningIND

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 15:19 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

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.

Cncnati-Daytn, OH (KILN), 12:00Z

6.0 hours before the tornado, 191 km from the path. September 20, 2002.

Skew-T log-pSkew-T log-p diagram, Cncnati-Daytn, OH at 12:00Z on 2002-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 339 joules per kilogram, CIN -46, lifted condensation level 850 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, Cncnati-Daytn, OH at 12:00Z on 2002-09-20The 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 153 square meters per square second, 0 to 6 km bulk shear 39 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
339 J/kg
Mixed-layer CIN
-46 J/kg
Surface CAPE
252 J/kg
Mixed-layer LCL
850 m above ground
0-6 km bulk shear
39 kt
0-1 km bulk shear
21 kt
0-1 km storm-relative helicity
153 m²/s²
0-3 km storm-relative helicity
179 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.5
0-3 km lapse rate
5.1 K/km

Open this sounding in Storm Lab

Cncnati-Daytn, OH (KILN), 00:00Z

6.0 hours after it, 191 km from the path. September 21, 2002.

Skew-T log-pSkew-T log-p diagram, Cncnati-Daytn, OH at 00:00Z on 2002-09-21Temperature 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 -77180, lifted condensation level 857 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, Cncnati-Daytn, OH at 00:00Z on 2002-09-21The 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 -195 square meters per square second, 0 to 6 km bulk shear 38 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
-77180 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
857 m above ground
0-6 km bulk shear
38 kt
0-1 km bulk shear
23 kt
0-1 km storm-relative helicity
-195 m²/s²
0-3 km storm-relative helicity
30 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.3 K/km

Open this sounding in Storm Lab

The surface observations

Indianapolis (EYE), 29 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
16:02 UTC69.868160° 6 kt1008.1-RA
16:34 UTC69.869.8160° 6 kt1007.5-RA
16:53 UTC7069150° 3 kt1007.1
17:09 UTC71.669.8160° 7 kt1006.8
17:28 UTC71.671.6160° 9 kt1006.4
17:53 UTC7271160° 9 kt1006.1BR
18:00 UTC73.471.6160° 7 kt1005.8BR
18:31 UTC73.471.6130° 6 kt1005.1-TSRA BR
18:39 UTC73.471.6140° 7 kt1004.7RA BR
18:44 UTC73.471.6230° 11 kt1006.1TSRA BR
19:11 UTC6864.4260° 11 kt251006.4RA BR
19:22 UTC66.264.4250° 9 kt171006.1TSRA BR
19:33 UTC66.264.4230° 10 kt1006.8+TSRA BR
19:36 UTC66.264.4220° 8 kt161006.8VCTS +RA BR
19:45 UTC66.264.4230° 8 kt1006.4VCTS RA BR
19:53 UTC6664230° 7 kt1006.4VCTS RA BR

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

The radar

The Indianapolis radar (KIND), 32 km away, was scanning. The volume nearest the touchdown began at 17:58 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

This ground now

The live radar over the trackEvery 2002 tornado in IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

The other tornadoes of September 20, 2002

7 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 2010:40 AM CDTF0Posey, IN0.240
September 2010:50 AM CDTF2Posey, IN4.71501$500,000
September 2011:35 AM ESTF2Pike, IN13.51502$1.0 million
September 202:47 PM ESTF2Henry, IN6.0100$2.0 million
September 203:03 PM ESTF0Rush, IN1.0100$500,000
September 204:41 PM EDTF1Allen, OH0.125$50,000
September 205:15 PM EDTF0Van Wert, OH4.0100

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.