Tornadoes · United States · Alabama · 2021

EF1 tornado, Siloam to Epes, Alabama, March 17, 2021

From Siloam to Epes, this EF1 tornado ran 9.8 miles across Sumter County on March 17, 2021, touching down at 12:57 PM CDT and reaching 475 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 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
March 17, 2021
Touchdown
12:57 PM CDT (17:57 UTC)
Lifted
1:15 PM CDT (18:15 UTC)
On the ground
18 minutes
Path length
9.8 miles (15.7 km)
Path width
475 yards (434 m)
Deaths
0
Injuries
0
County
Sumter County
Touchdown point
32.539, -88.134
Lift-off point
32.676, -88.107
Record number
2103171157-01

The damage survey

50 damage points were recorded along this path by NWS BMX, in the Damage Assessment Toolkit the survey teams carry. The strongest indicator was rated EF1. The highest wind the damage implies is 105 mph.

  • Extensive amount of pine trees downed.
  • Church. Couple branches snapped nearby.

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

An active southern jet stream set-up across the southern United States during the middle of March. Several short-wave troughs became negatively tilted as each one traversed across Texas and towards Alabama. This resulted in a single hail event one Monday, March 15, and significant tornado outbreak on Wednesday, March 17. Many supercells began to develop across Central Alabama by midday Wednesday and continued into the evening hours before a squall line moved through the state. Sufficient instability and strong wind shear produced conditions favorable for tornadoes to develop. The event consisted of twenty-one tornadoes in the NWS Birmingham forecast area.

National Weather Service meteorologists surveyed damage in southern Sumter County and determined that it was consistent with an EF0 tornado, with maximum winds near 75 mph. The tornado began and ended near the intersection of Walker Road and Highway 17. Damage consisted of uprooted trees, broken large tree branches, and shingle damage to a residence.

National Weather Service meteorologists surveyed damage in east central Sumter County and determined that it was consistent with an EF1 tornado, with maximum winds near 105 mph. A tornado touched down on the south side of Highway 28 East just west of Adams Drive. The tornado traveled north and produced mostly tree damage, with numerous hardwood and softwood trees snapped or uprooted. A home in the Bluffport community lost part of its roof and a mobile home was shifted from its blocks. The tornado lifted just north of Port of Epes Highway.

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.

The county was under a tornado watch, issued at 16:36 UTC and running to 23:48 UTC.

Issued (UTC)ExpiredProductOffice
03:11 UTC03:35 UTCSevere Thunderstorm WarningBMX
16:36 UTC23:48 UTCTornado WatchBMX
17:59 UTC18:25 UTCTornado WarningBMX
18:52 UTC19:17 UTCTornado WarningBMX
19:47 UTC22:00 UTCFlood AdvisoryBMX
22:26 UTC01:30 UTCFlood AdvisoryBMX
23:48 UTC02:04 UTCTornado WatchBMX
01:01 UTC01:23 UTCTornado WarningBMX

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 High Risk, with a 0.45 chance of a tornado within 25 miles, in the hatched area where significant tornadoes were expected. The outlook in force was issued at 16:06 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.

Birmingham, AL (KBMX), 12:00Z

6.0 hours before the tornado, 140 km from the path. March 17, 2021.

Skew-T log-pSkew-T log-p diagram, Birmingham, AL at 12:00Z on 2021-03-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 658 joules per kilogram, CIN -112, lifted condensation level 759 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Birmingham, AL at 12:00Z on 2021-03-17The 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 169 square meters per square second, 0 to 6 km bulk shear 59 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
658 J/kg
Mixed-layer CIN
-112 J/kg
Surface CAPE
2 J/kg
Mixed-layer LCL
759 m above ground
0-6 km bulk shear
59 kt
0-1 km bulk shear
14 kt
0-1 km storm-relative helicity
169 m²/s²
0-3 km storm-relative helicity
301 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.1
0-3 km lapse rate
4.5 K/km

Open this sounding in Storm Lab

Birmingham, AL (KBMX), 00:00Z

6.0 hours after it, 140 km from the path. March 18, 2021.

Skew-T log-pSkew-T log-p diagram, Birmingham, AL at 00:00Z on 2021-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 188 joules per kilogram, CIN -25, lifted condensation level 669 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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, Birmingham, AL at 00:00Z on 2021-03-18The 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 336 square meters per square second, 0 to 6 km bulk shear 63 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
188 J/kg
Mixed-layer CIN
-25 J/kg
Surface CAPE
21 J/kg
Mixed-layer LCL
669 m above ground
0-6 km bulk shear
63 kt
0-1 km bulk shear
39 kt
0-1 km storm-relative helicity
336 m²/s²
0-3 km storm-relative helicity
465 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6
0-3 km lapse rate
5.2 K/km

Open this sounding in Storm Lab

The surface observations

Demopolis (DYA), 22 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
16:15 UTC74.571.8150° 7 kt1012.5
16:35 UTC7571160° 6 kt1012.2
16:55 UTC7470.3140° 6 kt1011.9RA
17:15 UTC73.270.7140° 5 kt1011.2RA
17:35 UTC72.572.50° 0 kt1010.8-RA
17:55 UTC7272120° 4 kt1010.5-RA
18:15 UTC71.871.8120° 6 kt1009.8
18:35 UTC7271.8130° 4 kt1010.5+RA
18:55 UTC71.471.4300° 16 kt211008.8+RA
19:15 UTC71.671.6150° 10 kt1009.5-RA
19:35 UTC6967160° 7 kt1009.5-RA
19:55 UTC67.867.3130° 4 kt1008.8-RA

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

The radar

The Birmingham radar (KBMX), 141 km away, was scanning. The volume nearest the touchdown began at 17:56 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
17:31 UTCTORNADO4 Nne WardSumter, ALA NWS SURVEY TEAM CONFIRMED DAMAGE FROM A BRIEF EF-0 TORNADO IN SOUTHERN SUMTER COUNTY. THE TORNADO BEGAN AND ENDED NEAR THE INTERSECTION OF WALKER ROAD AND HIGHWAY 17. DAMAGE CONSISTED OF UPROOTED TREES, BROKEN LARGE TR
17:37 UTCTSTM WND DMG4 Nne WardSumter, AL20 TO 30 TREES BLOWN DOWN AND MINOR STRUCTURAL DAMAGE NEAR HIGHWAY 17 AND WALKER ROAD.
17:37 UTCTSTM WND DMG4 Nne WardSumter, ALCORRECTS PREVIOUS TSTM WND DMG REPORT FROM 4 NNE WARD. 20 TO 30 TREES BLOWN DOWN AND MINOR STRUCTURAL DAMAGE NEAR HIGHWAY 17 AND WALKER ROAD. POSSIBLE TORNADO.
17:57 UTCTORNADO4 N LilitaSumter, ALA NWS SURVEY TEAM CONFIRMED DAMAGE FROM AN EF1 TORNADO THAT BEGAN ON THE SOUTH SIDE OF HIGHWAY 28E JUST EAST OF LIVINGSTON AND ENDED NEAR PORT OF EPES HIGHWAY ON APPROACH TO THE TOMBIGBEE RIVER. NUMEROUS HARDWOOD AND SOF
18:02 UTCTSTM WND DMGBluffportSumter, ALSEVERAL TREES WERE BLOWN DOWN AND AT LEAST 4 STRUCTURES WERE DAMAGED IN BLUFFPORT. DAMAGE WAS REPORTED AT HIGHWAY 21 AND VALLEY ROAD. POSSIBLE TORNADO.
19:03 UTCTORNADO2 Ese McdowellMarengo, ALA NWS SURVEY TEAM CONFIRMED A BRIEF EF0 TORNADO THAT CROSSED LOCK AND DAM ROAD JUST WEST OF FOSCUE PARK, OUTSIDE OF THE CITY OF DEMOPOLIS. DAMAGE CONSISTED OF UPROOTED TREES, LARGE TREE BRANCHES BROKEN, AND SOME PANELING
19:05 UTCTORNADO2 Wnw DemopolisSumter, ALTORNADO OBSERVED VIA TV STATION WEBCAM BROADCAST WITH POWER FLASH AND STORM CHASER DRONE VIDEO.
19:12 UTCTORNADO1 E Mound State ParkHale, ALAN EF1 TORNADO PRODUCED DAMAGE FOR 22.03 MILES AND WAS 550 YARDS WIDE AT ITS WIDEST POINT. THE TORNADO STARTED IN MARTIN SLOUGH EAST OF THE WARRIOR RIVER AND LIFTED NNW OF DUNCANVILLE. MODERATE STRUCTURE DAMAGE AND TREE
19:22 UTCTORNADO3 Sw Sweet WaterMarengo, ALNWS METEOROLOGISTS SURVEYED DAMAGE SOUTH OF SWEET WATER AND DETERMINED THAT IT WAS CONSISTENT WITH AN EF1 TORNADO. THE TORNADO BEGAN ALONG MARENGO COUNTY 6. IT CONTINUED NORTHEASTWARD AND REACHED ITS MAXIMUM INTENSITY AL
19:29 UTCTORNADO1 E Mound State ParkHale, ALROOF DAMAGE TO A NUMBER OF HOUSES IN THE CITY ON BOTH SIDES OF THE COUNTY LINE. SEVERAL BUSINESSES DAMAGED IN MOUNDVILLE.
19:31 UTCTORNADO2 Ene Mound State ParkTuscaloosa, ALMULTIPLE HOMES DAMAGED IN THE WATERBURY SUBDIVISION.

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

This ground now

The live radar over the trackEvery 2021 tornado in AlabamaEvery tornado in Alabama since 1950Warnings in force in Alabama nowThe forecast where you are

The other tornadoes of March 17, 2021

32 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
March 1712:03 PM CDTEF2Wayne, MS13.1325
March 1712:31 PM CDTEF0Sumter, AL0.370
March 1712:32 PM CDTEF2Dallas, AL5.11,0002
March 171:16 PM CDTEF1Lincoln, MS6.2120$20,000
March 171:24 PM CDTEF1Autauga, AL2.9150
March 171:56 PM CDTEF1Chilton, AL3.0500
March 172:03 PM CDTEF0Marengo, AL0.8175
March 172:12 PM CDTEF1Hale, AL22.0550
March 172:22 PM CDTEF1Marengo, AL2.8500
March 172:26 PM CDTEF1Union Parish, LA2.6766$150,000
March 172:29 PM CDTEF0Coosa, AL0.125
March 173:09 PM CDTEF1Tuscaloosa, AL0.5150
March 173:25 PM CDTEF1Tuscaloosa, AL3.5650
March 173:44 PM CDTEF2Wayne, MS to AL36.65002
March 173:54 PM CDTEF1Tuscaloosa, AL5.8650
March 174:07 PM CDTEF1Wilkinson, MS6.8100
March 174:11 PM CDTEF0Dallas, AL1.175
March 174:30 PM CDTEF1Jefferson, AL2.8650
March 174:37 PM CDTEF0Desha, AR0.110
March 174:54 PM CDTEF0Marengo, AL1.875
March 174:56 PM CDTEF0Jefferson, AL3.56601
March 175:12 PM CDTEF2Chilton, AL5.8400
March 175:30 PM CDTEF1Barry, MO23.775$60,000
March 175:43 PM CDTEF1Blount, AL12.9300
March 176:16 PM CDTEF0Lamar, MS1.4300$75,000
March 177:25 PM CDTEF0Chickasaw, MS0.550$25,000
March 177:31 PM CDTEF0Chickasaw, MS1.4100$25,000
March 177:39 PM CDTEF0Lee, MS4.960$35,000
March 177:56 PM CDTEF0Kemper, MS0.280$5,000
March 178:35 PM CDTEF0Autauga, AL0.175
March 179:31 PM CDTEF1Cullman, AL8.5150
March 1710:43 PM CDTEF0Montgomery, AL0.3140

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.