Tornadoes · United States · Georgia · 2021

EF1 tornado, Riverdale, Georgia, March 1, 2021

Name: EF1 tornado, Riverdale, Georgia, March 1, 2021
Start: 2021-03-01T11:04:00.000Z
End: 2021-03-01T11:05:00.000Z
Location: Riverdale, Georgia

This EF1 tornado ran 0.7 miles across Clayton County on March 1, 2021, touching down at 6:04 AM EST and reaching 100 yards wide. It killed nobody, and did $250,000 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.

EF065 to 85 mph
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
EF186 to 110 mphthis tornado
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
EF4166 to 200 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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: March 1, 2021
Touchdown: 6:04 AM EST (11:04 UTC)
Lifted: 6:05 AM EST (11:05 UTC)
On the ground: 1 minutes
Path length: 0.7 miles (1.2 km)
Path width: 100 yards (91 m)
Deaths: 0
Injuries: 0
Property damage: $250,000
County: Clayton County
Touchdown point: 33.567, -84.453
Lift-off point: 33.560, -84.443
Record number: 2103010504-01

The damage survey

21 damage points were recorded along this path by NWS FFC, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 90 mph.

Majority of trees fell to south/southeast (south of storm motion (sw-ne))
Location point... no damage/debris on ground indicating "path"

Survey points are preliminary and are the raw material the published rating was built from. Source: NWS Damage Assessment Toolkit.

What the Weather Service recorded

Strong low-level shear and marginal instability ahead of a strong cold front sweeping through the region combined to produce a few strong to severe thunderstorms, and an tornado, across parts of north Georgia.

A National Weather Service survey determined that an EF1 tornado with maximum wind speeds of 90 MPH and a maximum path width of 100 yards briefly touched down in Clayton County. Damage was first surveyed along Bethsaida Road near the intersection with Lakefield Forrest Drive where several trees were uprooted or snapped and several power lines were blown down. The tornado moved southeast reaching its maximum intensity as it crossed West Fayetteville Road snapping or uprooting numerous trees, including several which fell onto homes along Bethaven Road and Zebulon Court. The tornado continued southeast along Bethaven Road, lifting before it reached the intersection of Bethaven road and Monarch Drive. [3/1/21: Tornado #1, County #1/1, EF-1, Clayton, 2021:005].

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.

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 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.

Peachtre/Fal Fld, GA (KFFC), 00:00Z

11.1 hours before the tornado, 22 km from the path. March 1, 2021.

Skew-T log-p

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.

Hodograph

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: 53 J/kg
Mixed-layer CIN: -9 J/kg
Surface CAPE: 210 J/kg
Mixed-layer LCL: 1337 m above ground
0-6 km bulk shear: 43 kt
0-1 km bulk shear: 16 kt
0-1 km storm-relative helicity: 117 m²/s²
0-3 km storm-relative helicity: 162 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2
0-3 km lapse rate: 6.0 K/km

Open this sounding in Storm Lab

Peachtre/Fal Fld, GA (KFFC), 12:00Z

0.9 hours after it, 22 km from the path. March 1, 2021.

Skew-T log-p

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.

Hodograph

Mixed-layer CAPE: 147 J/kg
Mixed-layer CIN: -17 J/kg
Surface CAPE: 214 J/kg
Mixed-layer LCL: 672 m above ground
0-6 km bulk shear: 68 kt
0-1 km bulk shear: 49 kt
0-1 km storm-relative helicity: 343 m²/s²
0-3 km storm-relative helicity: 317 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.3
0-3 km lapse rate: 6.2 K/km

Open this sounding in Storm Lab

The radar

The Atlanta radar (KFFC), 25 km away, was scanning. The volume nearest the touchdown began at 11:02 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)	Report	Where	County	Remark
10:13 UTC	TSTM WND DMG	3 E New Georgia	Paulding, GA	STRONG WINDS DESTROYED A FENCE AND SNAPPED A FEW TREE LIMBS NEAR THE INTERSECTION OF WAYNE MEADOWS CT AND BRAMLETT MEADOWS DR. SOME DEBRIS FROM THE FENCE DID DAMAGE ANOTHER HOME DOWN THE STREET.
10:20 UTC	TSTM WND DMG	2 Nnw Jim R Miller Park	Cobb, GA	SEVERAL PINE TREES WERE SNAPPED OR UPROOTED IN THE WYCKFORD SUBDIVISION.
10:20 UTC	TSTM WND DMG	3 E New Georgia	Paulding, GA	SEVERAL TREES DOWNED ALONG WAYNE MEADOWS CT.
11:00 UTC	TSTM WND DMG	2 Wsw Riverdale	Clayton, GA	MULTIPLE LARGE TREES BLOWN DOWN ALONG BETHAVEN ROAD...SOME TREES DOWN ON HOUSES.
11:05 UTC	TORNADO	2 W Riverdale	Clayton, GA	AN EF1 TORNADO WITH MAX WINDS 90MPH BRIEFLY TOUCHED DOWN IN CLAYTON COUNTY. DAMAGE WAS FIRST SURVEYED ALONG BETHSAIDA RD NEAR THE INTERSECTION OF LAKEFIELD FORREST DR WHERE SEVERAL TREES WERE UPROOTED OR SNAPPED NEXT TO
11:06 UTC	TSTM WND DMG	2 Nne Kenwood	Clayton, GA	* 1 FATAL * TREE FELL ON MAN AND TRUCK OUTSIDE HOME ON LAKEVIEW DR.

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

This ground now

The live radar over the track Every 2021 tornado in Georgia Every tornado in Georgia since 1950 Warnings in force in Georgia now The 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.