Tornadoes · United States · North Carolina · 2011

EF0 tornado, Unionville, North Carolina, September 5, 2011

This EF0 tornado ran 0.5 miles across Union County on September 5, 2011, touching down at 7:51 PM EDT and reaching 40 yards wide. It killed nobody.

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 mphthis tornado

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

  2. EF186 to 110 mph

    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
EF0
Date
September 5, 2011
Touchdown
7:51 PM EDT (23:51 UTC)
Lifted
7:52 PM EDT (23:52 UTC)
On the ground
1 minutes
Path length
0.5 miles (0.8 km)
Path width
40 yards (37 m)
Deaths
0
Injuries
0
County
Union County
Touchdown point
35.067, -80.556
Lift-off point
35.073, -80.552
Record number
1109051751-01

What the Weather Service recorded

As the remnants of tropical cyclone ���Lee��� moved toward the region, increasing wind shear and instability resulted in a few low topped, rotating thunderstorms. Despite the storms' having strong mid-level rotation on radar, only one of them went on to produce a tornado over the North Carolina piedmont. A little straight-line wind damage was also reported over the region.

This brief, weak tornado touched down at a farm site just southwest of the intersection of Ridge Rd and C.J. Thomas Rd. The tornado traveled around one-half mile before lifting near Bernard Thompson Rd. A few barns received roof damage and some trees were blown down.

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

The warnings

4 minutes of warning. NWS GSP issued a tornado warning for this county at 23:47 UTC, 4 minutes before the tornado touched down, in force until 00:19 UTC.

The county was under a tornado watch, issued at 19:43 UTC and running to 02:32 UTC.

Issued (UTC)ExpiredProductOffice
16:00 UTC19:46 UTCFlash Flood WatchGSP
19:43 UTC02:32 UTCTornado WatchGSP
23:47 UTC00:19 UTCTornado WarningGSP

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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:45 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.

Greensboro/Hi Pt, NC (KGSO), 12:00Z

11.9 hours before the tornado, 127 km from the path. September 5, 2011.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 12:00Z on 2011-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 109 joules per kilogram, CIN -38, lifted condensation level 689 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, Greensboro/Hi Pt, NC at 12:00Z on 2011-09-05The 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 62 square meters per square second, 0 to 6 km bulk shear 46 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
109 J/kg
Mixed-layer CIN
-38 J/kg
Surface CAPE
35 J/kg
Mixed-layer LCL
689 m above ground
0-6 km bulk shear
46 kt
0-1 km bulk shear
19 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
48 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

Greensboro/Hi Pt, NC (KGSO), 00:00Z

0.1 hours after it, 127 km from the path. September 6, 2011.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 00:00Z on 2011-09-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1522 joules per kilogram, CIN -14, lifted condensation level 698 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, Greensboro/Hi Pt, NC at 00:00Z on 2011-09-06The 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 209 square meters per square second, 0 to 6 km bulk shear 48 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
1522 J/kg
Mixed-layer CIN
-14 J/kg
Surface CAPE
847 J/kg
Mixed-layer LCL
698 m above ground
0-6 km bulk shear
48 kt
0-1 km bulk shear
26 kt
0-1 km storm-relative helicity
209 m²/s²
0-3 km storm-relative helicity
245 m²/s²
Significant tornado parameter
2.1
Supercell composite
9.5
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

The radar

The Columbia radar (KCAE), 135 km away, was scanning. The volume nearest the touchdown began at 23:52 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
23:10 UTCTSTM WND DMG5 Nw CharlotteMecklenburg, NCA FEW TREES AND LIMBS DOWN AT TUCKASEEGEE PARK. TIME IS BASED ON WHEN STRONGEST STORM PASSED OVER THIS LOCATION. NOBODY WAS AROUND ON LABOR DAY TO SEE THIS OCCUR.
23:50 UTCHAIL 1.757 Nnw MonroeUnion, NCUP TO GOLF BALL SIZED HAIL REPORTED AT PORTER RIDGE HIGH SCHOOL IN INDIAN TRAIL, NC.
23:50 UTCTORNADO7 Nnw MonroeUnion, NCSPOTTER RELAYED A REPORT FROM THE PUBLIC OF A FUNNEL CLOUD TOUCHING DOWN FOR APPROXIMATELY 2 MINTUES NEXT TO PORTER RIDGE HIGH SCHOOL IN INDIAN TRAIL, NC. TIME OF TOUCHDOWN ESTIMATED AT 750 PM LOCAL TIME.
23:54 UTCTSTM WND DMG6 N MonroeUnion, NCIN ADDITION TO THE PREVIOUSLY REPORTED DAMAGE TO BARNS AND TIN ROOFS ON RIDGE ROAD NEAR C.J. THOMAS ROAD...THERE WERE ALSO TREES DOWN IN THE AREA.
23:54 UTCTORNADO6 N MonroeUnion, NCSTATE PATROL REPORTED DAMAGE TO BARNS AND TIN ROOFS ON RIDGE ROAD NEAR C.J. THOMAS ROAD.
23:59 UTCFUNNEL CLOUD7 Nw MonroeUnion, NCCONE SHAPE FUNNEL CLOUD SARDIS CHURCH AND UNIONVILLE INDIAN ROAD.
23:59 UTCHAIL 17 Nw MonroeUnion, NCSARDIS CHURCH AND UNIONVILLE INDIAN ROAD.
00:35 UTCTSTM WND DMG6 Nw CharlotteMecklenburg, NCPOWERLINES BLOWN DOWN 1200 MARBLE ROAD.
00:40 UTCFUNNEL CLOUD2 Se LocustStanly, NCLAW ENFORCEMENT REPORTED A FUNNEL CLOUD ON OAK GROVE ROAD IN LOCUST.
00:45 UTCFUNNEL CLOUDFingerStanly, NCFUNNEL CLOUD REPORTED BY PUBLIC.
00:45 UTCTORNADO2 Wnw PlylerStanly, NCNUMEROUS TREES AND POWER LINES WERE REPORTED DOWN IN THE MILLINGPORT AREA... NEAR HWY 73 AND MILLINGPORT RD.
00:47 UTCTSTM WND DMG3 Nnw AlbemarleStanly, NCTREE DOWN ON SNUGGS PARK ROAD
00:51 UTCTORNADO4 Sw RichfieldStanly, NCNUMEROUS TREES AND POWER LINES WERE REPORTED DOWN IN THE PAULS CROSSING AREA... ALONG PAULS CROSSING ROAD.
00:52 UTCTORNADO3 Sw RichfieldStanly, NCMEDIA REPORTED BARNS DESTROYED ON MILLER ROAD NEAR PAULS CROSSING

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

This ground now

The live radar over the trackEvery 2011 tornado in North CarolinaEvery tornado in North Carolina since 1950Warnings in force in North Carolina nowThe forecast where you are

The other tornadoes of September 5, 2011

8 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
September 512:00 PM CDTEF0Hale, AL3.450$12,000
September 512:57 PM CDTEF0Jackson, FL0.325$1,000
September 53:11 PM EDTEF1Cherokee, GA28.44401$20 million
September 55:16 PM EDTEF0Newberry, SC0.150
September 55:20 PM EDTEF1Wilkes, NC1.3250$850,000
September 56:05 PM EDTEF0Fluvanna, VA0.9100$10,000
September 58:53 PM EDTEF0Stanly, NC4.2100$35,000
September 510:03 PM EDTEF0Carroll, VA0.0502$300,000

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.