Tornadoes · United States · Indiana · 2009

EF1 tornado, Borden, Indiana, September 20, 2009

This EF1 tornado ran 1.1 miles across Clark County on September 20, 2009, touching down at 5:58 PM EDT and reaching 35 yards wide. It killed nobody, and did $10,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mphthis tornado

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 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. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 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
EF1
Date
September 20, 2009
Touchdown
5:58 PM EDT (21:58 UTC)
Lifted
5:59 PM EDT (21:59 UTC)
On the ground
1 minutes
Path length
1.1 miles (1.8 km)
Path width
35 yards (32 m)
Deaths
0
Injuries
0
Property damage
$10,000
County
Clark County
Touchdown point
38.498, -85.934
Lift-off point
38.503, -85.913
Record number
0909201558-01

What the Weather Service recorded

A mid level trough over moving over the Ohio Valley brought heavy rainfall and a few strong thunderstorms, one of which produced a weak tornado, to southern Indiana. Anywhere from three to five inches of rain fell over several hours. An already saturated ground led contributed to flash flooding conditions. The tornado was produced in response to some increase low and mid level shear as a the low pressure system moved through the area.

The tornado uprooted and snapped several large trees and destroyed a small shed on Daisy Hill Road north of Borden. One snapped tree came down onto the roof of a home doing considerable damage.

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

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

Issued (UTC)ExpiredProductOffice
21:27 UTC21:49 UTCTornado WarningLMK
23:37 UTC00:37 UTCFlood AdvisoryLMK
00:31 UTC09:30 UTCFlash Flood WarningLMK
01:17 UTC03:32 UTCFlood AdvisoryLMK
02:56 UTC06:00 UTCFlash Flood WarningLMK

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 General Thunderstorms Risk. The outlook in force was issued at 19:40 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

10.0 hours before the tornado, 211 km from the path. September 20, 2009.

Skew-T log-pSkew-T log-p diagram, Cncnati-Daytn, OH at 12:00Z on 2009-09-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 49 joules per kilogram, CIN -83, lifted condensation level 720 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 2009-09-20The 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 39 square meters per square second, 0 to 6 km bulk shear 20 knots.1939Sfc1 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
49 J/kg
Mixed-layer CIN
-83 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
720 m above ground
0-6 km bulk shear
20 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
39 m²/s²
0-3 km storm-relative helicity
80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
2.9 K/km

Open this sounding in Storm Lab

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

2.0 hours after it, 211 km from the path. September 21, 2009.

Skew-T log-pSkew-T log-p diagram, Cncnati-Daytn, OH at 00:00Z on 2009-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 619 joules per kilogram, CIN -5, lifted condensation level 460 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 00:00Z on 2009-09-21The 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 157 square meters per square second, 0 to 6 km bulk shear 14 knots.1939Sfc1 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
619 J/kg
Mixed-layer CIN
-5 J/kg
Surface CAPE
1050 J/kg
Mixed-layer LCL
460 m above ground
0-6 km bulk shear
14 kt
0-1 km bulk shear
28 kt
0-1 km storm-relative helicity
157 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

The surface observations

Louisville/Bowman (LOU), 38 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:37 UTC78.871.6150° 6 kt1015.2-RA
20:48 UTC78.871.6130° 5 kt1014.9
20:53 UTC7871140° 7 kt1014.9
21:18 UTC7771.6150° 6 kt1014.9
21:53 UTC78.871.6140° 5 kt1014.9
22:08 UTC7771.60° 0 kt1014.9-RA
22:31 UTC75.271.6140° 8 kt1014.9
22:53 UTC7671130° 7 kt1014.6TS
23:17 UTC75.271.6 5 kt1015.2VCTS -RA
23:41 UTC75.271.6 4 kt1015.6VCTS +RA BR
23:53 UTC74710° 0 kt1015.2VCTS RA BR

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

The radar

The Louisville radar (KLVX), 58 km away, was scanning. The volume nearest the touchdown began at 21:59 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.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
20:48 UTCHEAVY RAIN 2.5LeavenworthCrawford, INRAINFALL 2.50 INCHES SINCE 10 AM THIS MORNING... MOST OF WHICH FELL IN THE LAST TWO HOURS.
21:29 UTCFLOODLeavenworthCrawford, IN2 TO 3 INCHES OF WATER OVER HYW 66 ONE MILE SOUTH OF INTERSTATE 64. NEARLY ONE INCH OF RAIN IN LAST 45 MINNUTES.
21:42 UTCFLOOD4 Nw MauckportHarrison, IN4 INCHES OF WATER OVER DRIVE WAY AND ABOUT TO ENTER THE HOUSE.
21:50 UTCFLOODMartinsburgWashington, IN3 INCHES OF WATER FLOWING OVER DRIVEWAY FROM NEARBY FIELD.
21:59 UTCTORNADO2 Ne BordenClark, INCONFIRMED EF-1 TORNADO. PATH LENGTH .75 MILE WIDTH 35 YARDS. MINOR DAMAGE TO MODULAR HOME AND LARGE STAND OF HARDWOOD TREES.
22:21 UTCFLOOD2 E CorydonHarrison, INTWO INCHES OF STANDING WATER ON HWY 62 EAST OF CORYDON.
22:26 UTCHEAVY RAIN 3.31 Ese CorydonHarrison, IN3.00 INCHES OF RAIN IN LAST 60 MINUTES. 3.30 TOTAL RAIN TODAY.
22:38 UTCFLASH FLOOD2 N WyandotteCrawford, INROAD WASHED OUT NEAR SHAFER RIDGE ROAD AND WYANDOTTE CAVE ROAD
22:45 UTCFLASH FLOOD2 E CorydonHarrison, INNUMEROUS LOCATIONS ON HWY 64 EAST OF CORYDON WITH HIGH WATER. AS MUCH AS TEN INCHES DEEP.
00:13 UTCHEAVY RAIN 3.056 Sse MilltownHarrison, IN3.05 INCHES IN THE LAST 2.5 HOURS.
00:22 UTCFLASH FLOODCharlestownClark, INWATER RESCUE IN CHARLESTOWN
00:24 UTCFLASH FLOODCharlestownClark, INNUMEROUS STREETS IN CHARLESTOWN CLOSED DUE TO FLOODING INCLUDING BOHART... SUNNYSIDE... NORTHBOUND MAIN... MARKET AND CARRIAGE WAY.
00:28 UTCFLASH FLOODClarksvilleClark, INWATER RESCUE ON VAXTER AVE IN CLARKSVILLE
00:29 UTCFLASH FLOODSellersburgClark, INWATER RESCUE AT PERRY CROSSING ROAD NEAR COVERED BRIDGE CC OUTSIDE OF SELLERSBURG.
00:31 UTCFLASH FLOODGeorgetownFloyd, INTWO VEHICLES STUCK IN WATER AND BEING RESCUED AT GREENVILLE ROAD.
00:51 UTCFLASH FLOODNew AlbanyFloyd, INWATER RESCUE AT 8TH AND JACKSON

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2009 tornado in IndianaEvery tornado in Indiana since 1950Warnings in force in Indiana nowThe forecast where you are

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.