Tornadoes · United States · South Carolina · 2006

F0 tornado, St Stephen to Bonneau, South Carolina, May 20, 2006

From St Stephen to Bonneau, this F0 tornado ran 0.2 miles across Berkeley County on May 20, 2006, touching down at 6:33 PM EDT and reaching 100 yards wide. It killed nobody.

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 mphthis tornado

    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 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
F0
Date
May 20, 2006
Touchdown
6:33 PM EDT (22:33 UTC)
Path length
0.2 miles (0.3 km)
Path width
100 yards (91 m)
Deaths
0
Injuries
0
County
Berkeley County
Touchdown point
33.420, -79.920
Lift-off point
33.420, -79.920
Record number
553

What the Weather Service recorded

NWS storm survey found many tree tops twisted off and broken. Large bundled stack of culverts blown through a fence along Rediversion Road. Estimated wind speeds of 60 mph with a width of 300 feet and a path length of 1/4 mile. Tornado rated as F0.

Brief tornado touchdown with winds estimated at 60 mph. A few limbs down near Highway 52.

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

The warnings

2 minutes of warning. NWS CHS issued a tornado warning for this county at 22:31 UTC, 2 minutes before the tornado touched down, in force until 23:30 UTC.

The county was under a severe thunderstorm watch, issued at 19:37 UTC and running to 01:35 UTC.

Issued (UTC)ExpiredProductOffice
19:37 UTC01:35 UTCSevere Thunderstorm WatchCHS
21:56 UTC23:00 UTCSevere Thunderstorm WarningCHS
22:31 UTC23:30 UTCTornado WarningCHS
23:41 UTC00:15 UTCTornado WarningCHS
00:18 UTC00:40 UTCSevere Thunderstorm WarningCHS

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 20:01 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.

Charleston AFB, SC (KCHS), 12:00Z

10.6 hours before the tornado, 58 km from the path. May 20, 2006.

Skew-T log-pSkew-T log-p diagram, Charleston AFB, SC at 12:00Z on 2006-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 8 joules per kilogram, CIN -289, lifted condensation level 2105 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, Charleston AFB, SC at 12:00Z on 2006-05-20The 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 258 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
8 J/kg
Mixed-layer CIN
-289 J/kg
Surface CAPE
0 J/kg
Mixed-layer LCL
2105 m above ground
0-6 km bulk shear
48 kt
0-1 km bulk shear
30 kt
0-1 km storm-relative helicity
258 m²/s²
0-3 km storm-relative helicity
293 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.5 K/km

Open this sounding in Storm Lab

Charleston AFB, SC (KCHS), 00:00Z

1.4 hours after it, 58 km from the path. May 21, 2006.

Skew-T log-pSkew-T log-p diagram, Charleston AFB, SC at 00:00Z on 2006-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 1652 joules per kilogram, CIN -77, lifted condensation level 1772 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, Charleston AFB, SC at 00:00Z on 2006-05-21The 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 147 square meters per square second, 0 to 6 km bulk shear 33 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
1652 J/kg
Mixed-layer CIN
-77 J/kg
Surface CAPE
2429 J/kg
Mixed-layer LCL
1772 m above ground
0-6 km bulk shear
33 kt
0-1 km bulk shear
27 kt
0-1 km storm-relative helicity
147 m²/s²
0-3 km storm-relative helicity
218 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.2
0-3 km lapse rate
7.6 K/km

Open this sounding in Storm Lab

The surface observations

Charleston (CHS), 59 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:56 UTC8567170° 10 kt1009.5
21:56 UTC8667190° 10 kt1008.8
22:56 UTC8466200° 10 kt1009.1
23:56 UTC7862120° 8 kt1010.5

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

The radar

The Columbia radar (KCAE), 126 km away, was scanning. The volume nearest the touchdown began at 22:34 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
22:12 UTCTSTM WND DMG2 S CadesWilliamsburg, SCTREES DOWN. HAIL WAS ALSO REPORTED. SIZE UNKOWN.
22:25 UTCTSTM WND DMG4 S VanceOrangeburg, SCNUMEROUS TREES DOWN NEAR HIGHWAYS 45 AND 310...BETWEEN WELLS AND EUTAWVILLE. HAIL OF UNKNOWN SIZE ALSO OCCURRED.
22:28 UTCTSTM WND DMG3 N Saint StephenBerkeley, SCSEVERAL TREES DOWNED ALONG PLATT ROAD. TIME ESTIMATED BY RADAR.
22:33 UTCTORNADO1 N Saint StephenBerkeley, SCMANY TREE TOPS TWISTED OFF AND BROKEN. LARGE BUNDLED STACK OF CULVERTS BLOWN THROUGH A FENCE ALONG REDIVERSION ROAD. ESTIMATED MAGNITUDE F0. WINDS ESTIMATED AT 60 MPH. WIDTH 300 FEET. LENGTH 1/4 MILE.
22:42 UTCTSTM WND DMG2 W CrossBerkeley, SCTREES AND POWERLINES DOWN ON SHORTCUT ROAD OFF HIGHWAY 6.
22:52 UTCTSTM WND DMG5 N MurraysvilleBerkeley, SCWIND DAMAGE AT BOY SCOUT CAMPGROUND ON SOUTH SIDE OF LAKE MOULTRIE. ESTIMATED 60-70 MPH WIND.
22:52 UTCTSTM WND DMGBonneauBerkeley, SCROOF OFF A MOBILE HOME NEAR GENERAL WASHINGTON BLVD
22:55 UTCTSTM WND GST 0MacbethBerkeley, SCSPOTTER REPORTED 60 MPH WINDS AND DIME HAIL ON EAST SIDE OF LAKE MOULTRIE
23:15 UTCTSTM WND DMG4 Sw Farewell CornerBerkeley, SCLARGE LIMBS DOWN
23:41 UTCTSTM WND DMGGermantownCharleston, SCMCCLELLANVILLE FIRE DEPT REPORTED TREE DOWN ALONG RUTLEDGE RD.
23:41 UTCTORNADOBonneauBerkeley, SCFIRE CHEIF FROM BONNEAU REPORTS TORNADO ON GROUND NEAR HIGHWAY 52 NEAR THE KANGAROO GAS STATION. LIMBS DOWN.
23:43 UTCTORNADO 0BonneauBerkeley, SCFIRE CHEIF FROM BONNEAU REPORTS TORNADO ON GROUND NEAR HIGHWAY 52 NEAR THE KANGAROO GAS STATION. LIMBS DOWN.
00:00 UTCTSTM WND DMG5 Sw ManningClarendon, SCCLARENDON S.O. REPORTED TREES DOWN ON INTERSTATE 95 NORTHBOUND NEAR MILE MARKER 116. TIME ESTIMATED BASED ON RADAR.
00:08 UTCTSTM WND DMG10 Se ManningClarendon, SCCLARENDON S.O. REPORTED TREES DOWN ON US HIGHWAY 521 TOWARD THE WILLIAMSBURG COUNTY LINE. TIME ESTIMATED BASED ON RADAR.
00:25 UTCTSTM WND DMGSaint StephenBerkeley, SCCITGO GAS STATION IN ST. STEPHEN REPORTED PENNY HAIL AND STRONG WINDS THAT DAMAGED GAS PUMPS.
00:25 UTCTSTM WND DMG3 Ne LaneWilliamsburg, SCTREES DOWN ON HWY 377.
00:30 UTCTSTM WND DMG2 W AndrewsWilliamsburg, SCTREES UPROOTED INCLUDING A LARGE 40 YEAR OLD TREE. TREE FELL ON TRUCK. PORCH ON HOUSE SHIFTED. PEAR TREES BROKEN.
00:30 UTCHAIL 0.752 Ne Lake CityFlorence, SCHAIL REPORTED ON HWY 378.

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

This ground now

The live radar over the trackEvery 2006 tornado in South CarolinaEvery tornado in South Carolina since 1950Warnings in force in South Carolina nowThe forecast where you are

The other tornadoes of May 20, 2006

1 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 207:41 PM EDTF0Berkeley, SC0.110

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.